Parabola
Mathematics · FE Reference Handbook section
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 mathematics problem uses Parabola vertex form. Given coefficient (a) = 0.6000; x-value (x) = 0.0000; vertex x (h) = -3.0000; vertex y (k) = 1.0000, determine the y-value (y).
Given
Find
y-value (y)
Start with the thinking
- The governing relation printed in this handbook section is Parabola vertex form.
- Everything except y is given, so isolate y 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.
- Mathematics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that y stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning y = 6.4000 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 12.8000 — kept a factor of two that cancels in the correct rearrangement.
- 3.2000 — dropped that same factor in the other direction.
- 7.0400 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Mathematics → Parabola
A vertical curve profile is modeled as a parabola. Given curvature coefficient (a) = 0.2000 1/m; station offset (x) = 28.5000 m; vertex station (h) = 1.1000 m; vertex elevation (k) = 8.8000 m, determine the elevation (y) in m.
Given
Find
elevation (y), in m
Start with the thinking
- The governing relation printed in this handbook section is Parabola (vertex form).
- Everything except y is given, so isolate y 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.
- A vertical curve profile is modeled as a parabola.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for y:
Step 3 — List the givens: curvature coefficient (a) = 0.2000 1/m, station offset (x) = 28.5000 m, vertex station (h) = 1.1000 m, vertex elevation (k) = 8.8000 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning y = 159.0 m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 317.9 — kept a factor of two that cancels in the correct rearrangement.
- 79.4760 — dropped that same factor in the other direction.
- 174.8 — rounded an intermediate value before the final step.
Reference: FE Handbook — Conic Sections (Parabola)
A mathematics problem uses Parabola vertex form. Given x-value (x) = -3.0000; vertex x (h) = -2.5000; vertex y (k) = 2.5000; y-value (y) = 11.2000, determine the coefficient (a).
Given
Find
coefficient (a)
Start with the thinking
- The governing relation printed in this handbook section is Parabola vertex form.
- Everything except a is given, so isolate a 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.
- Mathematics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that a stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning a = 34.8000 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 69.6000 — kept a factor of two that cancels in the correct rearrangement.
- 17.4000 — dropped that same factor in the other direction.
- 38.2800 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Mathematics → Parabola
A vertical curve profile is modeled as a parabola. Given elevation (y) = 12.5000 m; station offset (x) = 27.5000 m; vertex station (h) = 6.1000 m; vertex elevation (k) = 9.9000 m, determine the curvature coefficient (a) in 1/m.
Given
Find
curvature coefficient (a), in 1/m
Start with the thinking
- The governing relation printed in this handbook section is Parabola (vertex form).
- Everything except a is given, so isolate a 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.
- A vertical curve profile is modeled as a parabola.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for a:
Step 3 — List the givens: elevation (y) = 12.5000 m, station offset (x) = 27.5000 m, vertex station (h) = 6.1000 m, vertex elevation (k) = 9.9000 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning a = 0.0057 1/m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.0114 — kept a factor of two that cancels in the correct rearrangement.
- 0.0028 — dropped that same factor in the other direction.
- 0.0062 — rounded an intermediate value before the final step.
Reference: FE Handbook — Conic Sections (Parabola)
A mathematics problem uses Parabola vertex form. Given coefficient (a) = 2.0000; x-value (x) = 2.5000; vertex x (h) = -1.5000; y-value (y) = -38.8000, determine the vertex y (k).
Given
Find
vertex y (k)
Start with the thinking
- The governing relation printed in this handbook section is Parabola vertex form.
- Everything except k is given, so isolate k 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.
- Mathematics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that k stands alone on the left-hand side.
Step 3 — List the givens: coefficient (a) = 2.0000, x-value (x) = 2.5000, vertex x (h) = -1.5000, y-value (y) = -38.8000.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning k = -70.8000 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- -141.6 — kept a factor of two that cancels in the correct rearrangement.
- -35.4000 — dropped that same factor in the other direction.
- -77.8800 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Mathematics → Parabola
A vertical curve profile is modeled as a parabola. Given elevation (y) = 12.8000 m; curvature coefficient (a) = 0.3000 1/m; station offset (x) = 8.4000 m; vertex station (h) = 8.2000 m, determine the vertex elevation (k) in m.
Given
Find
vertex elevation (k), in m
Start with the thinking
- The governing relation printed in this handbook section is Parabola (vertex form).
- Everything except k is given, so isolate k 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.
- A vertical curve profile is modeled as a parabola.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for k:
Step 3 — List the givens: elevation (y) = 12.8000 m, curvature coefficient (a) = 0.3000 1/m, station offset (x) = 8.4000 m, vertex station (h) = 8.2000 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning k = 12.7880 m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 25.5760 — kept a factor of two that cancels in the correct rearrangement.
- 6.3940 — dropped that same factor in the other direction.
- 14.0668 — rounded an intermediate value before the final step.
Reference: FE Handbook — Conic Sections (Parabola)
A mathematics problem uses Parabola vertex form. Given coefficient (a) = 2.8000; x-value (x) = 4.0000; vertex x (h) = 1.5000; vertex y (k) = -1.0000, determine the y-value (y).
Given
Find
y-value (y)
Start with the thinking
- The governing relation printed in this handbook section is Parabola vertex form.
- Everything except y is given, so isolate y 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.
- Mathematics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that y stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning y = 16.5000 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 33.0000 — kept a factor of two that cancels in the correct rearrangement.
- 8.2500 — dropped that same factor in the other direction.
- 18.1500 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Mathematics → Parabola
A vertical curve profile is modeled as a parabola. Given curvature coefficient (a) = 0.2000 1/m; station offset (x) = 17.5000 m; vertex station (h) = 1.3000 m; vertex elevation (k) = 12.3000 m, determine the elevation (y) in m.
Given
Find
elevation (y), in m
Start with the thinking
- The governing relation printed in this handbook section is Parabola (vertex form).
- Everything except y is given, so isolate y 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.
- A vertical curve profile is modeled as a parabola.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for y:
Step 3 — List the givens: curvature coefficient (a) = 0.2000 1/m, station offset (x) = 17.5000 m, vertex station (h) = 1.3000 m, vertex elevation (k) = 12.3000 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning y = 64.7880 m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 129.6 — kept a factor of two that cancels in the correct rearrangement.
- 32.3940 — dropped that same factor in the other direction.
- 71.2668 — rounded an intermediate value before the final step.
Reference: FE Handbook — Conic Sections (Parabola)
A mathematics problem uses Parabola vertex form. Given x-value (x) = 3.0000; vertex x (h) = 2.5000; vertex y (k) = 3.0000; y-value (y) = -17.1000, determine the coefficient (a).
Given
Find
coefficient (a)
Start with the thinking
- The governing relation printed in this handbook section is Parabola vertex form.
- Everything except a is given, so isolate a 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.
- Mathematics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that a stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning a = -80.4000 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- -160.8 — kept a factor of two that cancels in the correct rearrangement.
- -40.2000 — dropped that same factor in the other direction.
- -88.4400 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Mathematics → Parabola
A vertical curve profile is modeled as a parabola. Given elevation (y) = 32.8000 m; station offset (x) = 14.0000 m; vertex station (h) = 8.0000 m; vertex elevation (k) = 8.9000 m, determine the curvature coefficient (a) in 1/m.
Given
Find
curvature coefficient (a), in 1/m
Start with the thinking
- The governing relation printed in this handbook section is Parabola (vertex form).
- Everything except a is given, so isolate a 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.
- A vertical curve profile is modeled as a parabola.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for a:
Step 3 — List the givens: elevation (y) = 32.8000 m, station offset (x) = 14.0000 m, vertex station (h) = 8.0000 m, vertex elevation (k) = 8.9000 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning a = 0.6639 1/m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 1.3278 — kept a factor of two that cancels in the correct rearrangement.
- 0.3319 — dropped that same factor in the other direction.
- 0.7303 — rounded an intermediate value before the final step.
Reference: FE Handbook — Conic Sections (Parabola)