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Quadric Surface (SPHERE)

Mathematics · FE Reference Handbook section

Mathematics
2 formulas
10 exam-style examples
~49 min
All Mathematics lectures

Handbook notes for this section

Definitions and conditions exactly as the handbook states them.

  • The standard form of the equation is
  • In a three-dimensional space, the distance between two points is

Core formulas for this FE topic

Definitions, applicability, units, assumptions and worked examples for each relation.

Worked exam-style examples

The four ways this section is written on the real exam — thoughts first, then equations, then substitution.

Example 1
Sphere volume and surface area — solve for volume — Quadric Surface (SPHERE)

A tank designer sizes a spherical storage vessel. Given radius (r) = 8.8000 ft; surface area (S) = 697.0 ft^2, determine the volume (V) in ft^3.

Given

  • radius(r)=8.8000ftradius (r) = 8.8000 ft
  • surfacearea(S)=697.0ft2surface area (S) = 697.0 ft^2

Find

volume (V), in ft^3

Start with the thinking

  • The governing relation printed in this handbook section is Sphere volume and surface area.
  • Everything except V is given, so isolate V symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • The sphere volume and surface area formulas relate the radius of a sphere to its volume and area.
r = Sphere geometry

Figure 1 — schematic for Sphere volume and surface area — solve for volume — Quadric Surface (SPHERE)

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  2. Step 2 — Rearrange symbolically for V:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  3. Step 3

    Listthegivens:radius(r)=8.8000ft,surfacearea(S)=697.0ft2List the givens: radius (r) = 8.8000 ft, surface area (S) = 697.0 ft^2
  4. Step 4 — Substitute the given values:

    V=43π8.80003V = \dfrac{4}{3}\pi 8.8000^3
  5. Step 5 — Evaluate:

    V = 2855\ \text{ft^3}
  6. Step 6 — Check: returning V = 2,855 ft^3 to

    V=43πr3V = \dfrac{4}{3}\pi r^3

    reproduces the given quantities, and both sides carry the same units.

Answer:
V = 2855\ \text{ft^3}

Why the other options are there

  • 5,709 — kept a factor of two that cancels in the correct rearrangement.
  • 1,427 — dropped that same factor in the other direction.
  • 3,140 — rounded an intermediate value before the final step.

Reference: FE Handbook — Sphere

Example 2
Sphere volume and surface area — solve for surface area — Quadric Surface (SPHERE) (2)

An engineer computes the volume of a spherical dome. Given radius (r) = 7.9000 ft; volume (V) = 46.0000 ft^3, determine the surface area (S) in ft^2.

Given

  • radius(r)=7.9000ftradius (r) = 7.9000 ft
  • volume(V)=46.0000ft3volume (V) = 46.0000 ft^3

Find

surface area (S), in ft^2

Start with the thinking

  • The governing relation printed in this handbook section is Sphere volume and surface area.
  • Everything except S is given, so isolate S symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • The sphere volume and surface area formulas relate the radius of a sphere to its volume and area.
r = Sphere geometry

Figure 2 — schematic for Sphere volume and surface area — solve for surface area — Quadric Surface (SPHERE) (2)

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  2. Step 2 — Rearrange symbolically for S:

    S=4πr2S = 4\pi r^2
  3. Step 3

    Listthegivens:radius(r)=7.9000ft,volume(V)=46.0000ft3List the givens: radius (r) = 7.9000 ft, volume (V) = 46.0000 ft^3
  4. Step 4 — Substitute the given values:

    S=4π7.90002S = 4\pi 7.9000^2
  5. Step 5 — Evaluate:

    S = 784.3\ \text{ft^2}
  6. Step 6 — Check: returning S = 784.3 ft^2 to

    V=43πr3V = \dfrac{4}{3}\pi r^3

    reproduces the given quantities, and both sides carry the same units.

Answer:
S = 784.3\ \text{ft^2}

Why the other options are there

  • 1,569 — kept a factor of two that cancels in the correct rearrangement.
  • 392.1 — dropped that same factor in the other direction.
  • 862.7 — rounded an intermediate value before the final step.

Reference: FE Handbook — Sphere

Example 3
Sphere volume and surface area — solve for radius — Quadric Surface (SPHERE) (3)

A student finds the surface area of a sphere given its radius. Given volume (V) = 4,045 ft^3; surface area (S) = 812.0 ft^2, determine the radius (r) in ft.

Given

  • volume(V)=4,045ft3volume (V) = 4,045 ft^3
  • surfacearea(S)=812.0ft2surface area (S) = 812.0 ft^2

Find

radius (r), in ft

Start with the thinking

  • The governing relation printed in this handbook section is Sphere volume and surface area.
  • Everything except r is given, so isolate r symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • The sphere volume and surface area formulas relate the radius of a sphere to its volume and area.
r = Sphere geometry

Figure 3 — schematic for Sphere volume and surface area — solve for radius — Quadric Surface (SPHERE) (3)

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  2. Step 2 — Rearrange symbolically for r:

    r=3V4π3r = \sqrt[3]{\dfrac{3V}{4\pi}}
  3. Step 3

    Listthegivens:volume(V)=4,045ft3,surfacearea(S)=812.0ft2List the givens: volume (V) = 4,045 ft^3, surface area (S) = 812.0 ft^2
  4. Step 4 — Substitute the given values:

    r=340454π3r = \sqrt[3]{\dfrac{34045}{4\pi}}
  5. Step 5 — Evaluate:

    r=9.8838 ftr = 9.8838\ \text{ft}
  6. Step 6 — Check: returning r = 9.8838 ft to

    V=43πr3V = \dfrac{4}{3}\pi r^3

    reproduces the given quantities, and both sides carry the same units.

Answer:
r=9.8838 ftr = 9.8838\ \text{ft}

Why the other options are there

  • 19.7677 — kept a factor of two that cancels in the correct rearrangement.
  • 4.9419 — dropped that same factor in the other direction.
  • 10.8722 — rounded an intermediate value before the final step.

Reference: FE Handbook — Sphere

Example 4
Sphere volume and surface area — solve for volume (case 2) — Quadric Surface (SPHERE) (4)

A tank designer sizes a spherical storage vessel. Given radius (r) = 5.5000 ft; surface area (S) = 1,044 ft^2, determine the volume (V) in ft^3.

Given

  • radius(r)=5.5000ftradius (r) = 5.5000 ft
  • surfacearea(S)=1,044ft2surface area (S) = 1,044 ft^2

Find

volume (V), in ft^3

Start with the thinking

  • The governing relation printed in this handbook section is Sphere volume and surface area.
  • Everything except V is given, so isolate V symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • The sphere volume and surface area formulas relate the radius of a sphere to its volume and area.
r = Sphere geometry

Figure 4 — schematic for Sphere volume and surface area — solve for volume (case 2) — Quadric Surface (SPHERE) (4)

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  2. Step 2 — Rearrange symbolically for V:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  3. Step 3

    Listthegivens:radius(r)=5.5000ft,surfacearea(S)=1,044ft2List the givens: radius (r) = 5.5000 ft, surface area (S) = 1,044 ft^2
  4. Step 4 — Substitute the given values:

    V=43π5.50003V = \dfrac{4}{3}\pi 5.5000^3
  5. Step 5 — Evaluate:

    V = 696.9\ \text{ft^3}
  6. Step 6 — Check: returning V = 696.9 ft^3 to

    V=43πr3V = \dfrac{4}{3}\pi r^3

    reproduces the given quantities, and both sides carry the same units.

Answer:
V = 696.9\ \text{ft^3}

Why the other options are there

  • 1,394 — kept a factor of two that cancels in the correct rearrangement.
  • 348.5 — dropped that same factor in the other direction.
  • 766.6 — rounded an intermediate value before the final step.

Reference: FE Handbook — Sphere

Example 5
Sphere volume and surface area — solve for surface area (case 2) — Quadric Surface (SPHERE) (5)

An engineer computes the volume of a spherical dome. Given radius (r) = 4.0000 ft; volume (V) = 1,611 ft^3, determine the surface area (S) in ft^2.

Given

  • radius(r)=4.0000ftradius (r) = 4.0000 ft
  • volume(V)=1,611ft3volume (V) = 1,611 ft^3

Find

surface area (S), in ft^2

Start with the thinking

  • The governing relation printed in this handbook section is Sphere volume and surface area.
  • Everything except S is given, so isolate S symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • The sphere volume and surface area formulas relate the radius of a sphere to its volume and area.
r = Sphere geometry

Figure 5 — schematic for Sphere volume and surface area — solve for surface area (case 2) — Quadric Surface (SPHERE) (5)

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  2. Step 2 — Rearrange symbolically for S:

    S=4πr2S = 4\pi r^2
  3. Step 3

    Listthegivens:radius(r)=4.0000ft,volume(V)=1,611ft3List the givens: radius (r) = 4.0000 ft, volume (V) = 1,611 ft^3
  4. Step 4 — Substitute the given values:

    S=4π4.00002S = 4\pi 4.0000^2
  5. Step 5 — Evaluate:

    S = 201.1\ \text{ft^2}
  6. Step 6 — Check: returning S = 201.1 ft^2 to

    V=43πr3V = \dfrac{4}{3}\pi r^3

    reproduces the given quantities, and both sides carry the same units.

Answer:
S = 201.1\ \text{ft^2}

Why the other options are there

  • 402.1 — kept a factor of two that cancels in the correct rearrangement.
  • 100.5 — dropped that same factor in the other direction.
  • 221.2 — rounded an intermediate value before the final step.

Reference: FE Handbook — Sphere

Example 6
Sphere volume and surface area — solve for radius (case 2) — Quadric Surface (SPHERE) (6)

A student finds the surface area of a sphere given its radius. Given volume (V) = 2,412 ft^3; surface area (S) = 1,227 ft^2, determine the radius (r) in ft.

Given

  • volume(V)=2,412ft3volume (V) = 2,412 ft^3
  • surfacearea(S)=1,227ft2surface area (S) = 1,227 ft^2

Find

radius (r), in ft

Start with the thinking

  • The governing relation printed in this handbook section is Sphere volume and surface area.
  • Everything except r is given, so isolate r symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • The sphere volume and surface area formulas relate the radius of a sphere to its volume and area.
r = Sphere geometry

Figure 6 — schematic for Sphere volume and surface area — solve for radius (case 2) — Quadric Surface (SPHERE) (6)

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  2. Step 2 — Rearrange symbolically for r:

    r=3V4π3r = \sqrt[3]{\dfrac{3V}{4\pi}}
  3. Step 3

    Listthegivens:volume(V)=2,412ft3,surfacearea(S)=1,227ft2List the givens: volume (V) = 2,412 ft^3, surface area (S) = 1,227 ft^2
  4. Step 4 — Substitute the given values:

    r=324124π3r = \sqrt[3]{\dfrac{32412}{4\pi}}
  5. Step 5 — Evaluate:

    r=8.3196 ftr = 8.3196\ \text{ft}
  6. Step 6 — Check: returning r = 8.3196 ft to

    V=43πr3V = \dfrac{4}{3}\pi r^3

    reproduces the given quantities, and both sides carry the same units.

Answer:
r=8.3196 ftr = 8.3196\ \text{ft}

Why the other options are there

  • 16.6392 — kept a factor of two that cancels in the correct rearrangement.
  • 4.1598 — dropped that same factor in the other direction.
  • 9.1516 — rounded an intermediate value before the final step.

Reference: FE Handbook — Sphere

Example 7
Sphere volume and surface area — solve for volume (case 3) — Quadric Surface (SPHERE) (7)

A tank designer sizes a spherical storage vessel. Given radius (r) = 2.5000 ft; surface area (S) = 104.5 ft^2, determine the volume (V) in ft^3.

Given

  • radius(r)=2.5000ftradius (r) = 2.5000 ft
  • surfacearea(S)=104.5ft2surface area (S) = 104.5 ft^2

Find

volume (V), in ft^3

Start with the thinking

  • The governing relation printed in this handbook section is Sphere volume and surface area.
  • Everything except V is given, so isolate V symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • The sphere volume and surface area formulas relate the radius of a sphere to its volume and area.
r = Sphere geometry

Figure 7 — schematic for Sphere volume and surface area — solve for volume (case 3) — Quadric Surface (SPHERE) (7)

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  2. Step 2 — Rearrange symbolically for V:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  3. Step 3

    Listthegivens:radius(r)=2.5000ft,surfacearea(S)=104.5ft2List the givens: radius (r) = 2.5000 ft, surface area (S) = 104.5 ft^2
  4. Step 4 — Substitute the given values:

    V=43π2.50003V = \dfrac{4}{3}\pi 2.5000^3
  5. Step 5 — Evaluate:

    V = 65.4498\ \text{ft^3}
  6. Step 6 — Check: returning V = 65.4498 ft^3 to

    V=43πr3V = \dfrac{4}{3}\pi r^3

    reproduces the given quantities, and both sides carry the same units.

Answer:
V = 65.4498\ \text{ft^3}

Why the other options are there

  • 130.9 — kept a factor of two that cancels in the correct rearrangement.
  • 32.7249 — dropped that same factor in the other direction.
  • 71.9948 — rounded an intermediate value before the final step.

Reference: FE Handbook — Sphere

Example 8
Sphere volume and surface area — solve for surface area (case 3) — Quadric Surface (SPHERE) (8)

An engineer computes the volume of a spherical dome. Given radius (r) = 5.9000 ft; volume (V) = 490.5 ft^3, determine the surface area (S) in ft^2.

Given

  • radius(r)=5.9000ftradius (r) = 5.9000 ft
  • volume(V)=490.5ft3volume (V) = 490.5 ft^3

Find

surface area (S), in ft^2

Start with the thinking

  • The governing relation printed in this handbook section is Sphere volume and surface area.
  • Everything except S is given, so isolate S symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • The sphere volume and surface area formulas relate the radius of a sphere to its volume and area.
r = Sphere geometry

Figure 8 — schematic for Sphere volume and surface area — solve for surface area (case 3) — Quadric Surface (SPHERE) (8)

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  2. Step 2 — Rearrange symbolically for S:

    S=4πr2S = 4\pi r^2
  3. Step 3

    Listthegivens:radius(r)=5.9000ft,volume(V)=490.5ft3List the givens: radius (r) = 5.9000 ft, volume (V) = 490.5 ft^3
  4. Step 4 — Substitute the given values:

    S=4π5.90002S = 4\pi 5.9000^2
  5. Step 5 — Evaluate:

    S = 437.4\ \text{ft^2}
  6. Step 6 — Check: returning S = 437.4 ft^2 to

    V=43πr3V = \dfrac{4}{3}\pi r^3

    reproduces the given quantities, and both sides carry the same units.

Answer:
S = 437.4\ \text{ft^2}

Why the other options are there

  • 874.9 — kept a factor of two that cancels in the correct rearrangement.
  • 218.7 — dropped that same factor in the other direction.
  • 481.2 — rounded an intermediate value before the final step.

Reference: FE Handbook — Sphere

Example 9
Sphere volume and surface area — solve for radius (case 3) — Quadric Surface (SPHERE) (9)

A student finds the surface area of a sphere given its radius. Given volume (V) = 120.1 ft^3; surface area (S) = 410.1 ft^2, determine the radius (r) in ft.

Given

  • volume(V)=120.1ft3volume (V) = 120.1 ft^3
  • surfacearea(S)=410.1ft2surface area (S) = 410.1 ft^2

Find

radius (r), in ft

Start with the thinking

  • The governing relation printed in this handbook section is Sphere volume and surface area.
  • Everything except r is given, so isolate r symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • The sphere volume and surface area formulas relate the radius of a sphere to its volume and area.
r = Sphere geometry

Figure 9 — schematic for Sphere volume and surface area — solve for radius (case 3) — Quadric Surface (SPHERE) (9)

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  2. Step 2 — Rearrange symbolically for r:

    r=3V4π3r = \sqrt[3]{\dfrac{3V}{4\pi}}
  3. Step 3

    Listthegivens:volume(V)=120.1ft3,surfacearea(S)=410.1ft2List the givens: volume (V) = 120.1 ft^3, surface area (S) = 410.1 ft^2
  4. Step 4 — Substitute the given values:

    r=3120.14π3r = \sqrt[3]{\dfrac{3120.1}{4\pi}}
  5. Step 5 — Evaluate:

    r=3.0607 ftr = 3.0607\ \text{ft}
  6. Step 6 — Check: returning r = 3.0607 ft to

    V=43πr3V = \dfrac{4}{3}\pi r^3

    reproduces the given quantities, and both sides carry the same units.

Answer:
r=3.0607 ftr = 3.0607\ \text{ft}

Why the other options are there

  • 6.1214 — kept a factor of two that cancels in the correct rearrangement.
  • 1.5303 — dropped that same factor in the other direction.
  • 3.3667 — rounded an intermediate value before the final step.

Reference: FE Handbook — Sphere

Example 10
Sphere volume and surface area — solve for volume (case 4) — Quadric Surface (SPHERE) (10)

A tank designer sizes a spherical storage vessel. Given radius (r) = 4.1000 ft; surface area (S) = 340.1 ft^2, determine the volume (V) in ft^3.

Given

  • radius(r)=4.1000ftradius (r) = 4.1000 ft
  • surfacearea(S)=340.1ft2surface area (S) = 340.1 ft^2

Find

volume (V), in ft^3

Start with the thinking

  • The governing relation printed in this handbook section is Sphere volume and surface area.
  • Everything except V is given, so isolate V symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • The sphere volume and surface area formulas relate the radius of a sphere to its volume and area.
r = Sphere geometry

Figure 10 — schematic for Sphere volume and surface area — solve for volume (case 4) — Quadric Surface (SPHERE) (10)

Step-by-step solution

  1. Step 1 — State the governing relation:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  2. Step 2 — Rearrange symbolically for V:

    V=43πr3V = \dfrac{4}{3}\pi r^3
  3. Step 3

    Listthegivens:radius(r)=4.1000ft,surfacearea(S)=340.1ft2List the givens: radius (r) = 4.1000 ft, surface area (S) = 340.1 ft^2
  4. Step 4 — Substitute the given values:

    V=43π4.10003V = \dfrac{4}{3}\pi 4.1000^3
  5. Step 5 — Evaluate:

    V = 288.7\ \text{ft^3}
  6. Step 6 — Check: returning V = 288.7 ft^3 to

    V=43πr3V = \dfrac{4}{3}\pi r^3

    reproduces the given quantities, and both sides carry the same units.

Answer:
V = 288.7\ \text{ft^3}

Why the other options are there

  • 577.4 — kept a factor of two that cancels in the correct rearrangement.
  • 144.3 — dropped that same factor in the other direction.
  • 317.6 — rounded an intermediate value before the final step.

Reference: FE Handbook — Sphere

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