Question

a bridge is built in the shape of a paraboolic arc. the bridge arch has a span of 152 feet and a max hight of 25 feet. find the hight of the arc at 20 feet from its center.

Answer 1

The parabola has a vertex at (0,25), so the equation of the parabola is
y = -ax^2+25. Since we know that the arch passes through (76,0), we put
0=-a(76)^2+25 => a=25/76^2
The final equation is then
y=-(25/76^2)x^2+25

at x=20, y=-(25/76^2)(20^2)+25=23.27'

Answer 2

thank you

Answer 3

yw! :)