Quadric Surface (SPHERE)
Mathematics · FE Reference Handbook section
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.
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
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.
Figure 1 — schematic for Sphere volume and surface area — solve for volume — Quadric Surface (SPHERE)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 2855\ \text{ft^3}Step 6 — Check: returning V = 2,855 ft^3 to
reproduces the given quantities, and both sides carry the same units.
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
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
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.
Figure 2 — schematic for Sphere volume and surface area — solve for surface area — Quadric Surface (SPHERE) (2)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for S:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
S = 784.3\ \text{ft^2}Step 6 — Check: returning S = 784.3 ft^2 to
reproduces the given quantities, and both sides carry the same units.
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
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
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.
Figure 3 — schematic for Sphere volume and surface area — solve for radius — Quadric Surface (SPHERE) (3)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for r:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning r = 9.8838 ft to
reproduces the given quantities, and both sides carry the same units.
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
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
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.
Figure 4 — schematic for Sphere volume and surface area — solve for volume (case 2) — Quadric Surface (SPHERE) (4)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 696.9\ \text{ft^3}Step 6 — Check: returning V = 696.9 ft^3 to
reproduces the given quantities, and both sides carry the same units.
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
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
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.
Figure 5 — schematic for Sphere volume and surface area — solve for surface area (case 2) — Quadric Surface (SPHERE) (5)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for S:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
S = 201.1\ \text{ft^2}Step 6 — Check: returning S = 201.1 ft^2 to
reproduces the given quantities, and both sides carry the same units.
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
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
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.
Figure 6 — schematic for Sphere volume and surface area — solve for radius (case 2) — Quadric Surface (SPHERE) (6)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for r:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning r = 8.3196 ft to
reproduces the given quantities, and both sides carry the same units.
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
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
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.
Figure 7 — schematic for Sphere volume and surface area — solve for volume (case 3) — Quadric Surface (SPHERE) (7)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 65.4498\ \text{ft^3}Step 6 — Check: returning V = 65.4498 ft^3 to
reproduces the given quantities, and both sides carry the same units.
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
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
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.
Figure 8 — schematic for Sphere volume and surface area — solve for surface area (case 3) — Quadric Surface (SPHERE) (8)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for S:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
S = 437.4\ \text{ft^2}Step 6 — Check: returning S = 437.4 ft^2 to
reproduces the given quantities, and both sides carry the same units.
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
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
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.
Figure 9 — schematic for Sphere volume and surface area — solve for radius (case 3) — Quadric Surface (SPHERE) (9)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for r:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning r = 3.0607 ft to
reproduces the given quantities, and both sides carry the same units.
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
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
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.
Figure 10 — schematic for Sphere volume and surface area — solve for volume (case 4) — Quadric Surface (SPHERE) (10)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 288.7\ \text{ft^3}Step 6 — Check: returning V = 288.7 ft^3 to
reproduces the given quantities, and both sides carry the same units.
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