Posted by **Sophie** on Tuesday, October 25, 2011 at 5:24pm.

An engineer is desingning a parabloic arch, the arch must be 15 m high , and 6 m wide, at a height of 8 m

a) determine a quadratic fundtion that satisfies these conditions

b) what is the width of the arch at its base

- Math -
**Steve**, Wednesday, October 26, 2011 at 4:42am
Let the arch be centered on the y-axis. Then the equation will be

y = -ax^2 + k

It will have height 6 at x = 3 and -3

The vertex will be at (0,15)

y = -ax^2 + 15

6 = -a(3^2) + 15

6 = -9a + 15

-9 = -9a

a = 1

y = -x^2 + 15

y=0 when x^2 = 15, so the width is 2√15 at its base

## Answer this Question

## Related Questions

- Math - An engineer is designing a parabolic arch. The arch must be 15 m high, ...
- Algebra II - The shape of a supporting arch can be modeled by h(x)= -0.03^2+3x, ...
- Math - The rainbow bridge of Utah is a natural arch that is approximately ...
- math - McDougal's Restaurant has a play area for children under and around their...
- Math - Question: A tunnel with a parabolic arch is 12 m wide. If the height of ...
- Math - gr.11 - A tunnel with a parabolic arch is 12m wide. If the height of the ...
- physics - in the distance you see an arch 192 meters high, you estimate your ...
- Algebra II - The question simply states-solve. -x^4+200=102x^2 I rearranged the ...
- Algebra word problem - A parabolic arch has a height of 20 m and a width of 36 m...
- Precalculus Trig (Geometry) - A large doorway has the shape of a parabolic arch...