A bridge is built in the shape of a parabolic arch. The bridge has a span of s 1
ID: 2912074 • Letter: A
Question
A bridge is built in the shape of a parabolic arch. The bridge has a span of s 180 feet and a maximum height of h 40 feet Choose a suitable rectangular coordinate system and find the height of the arch at distances of 10, 30, and 50 feet from the center. Find the height of the arch at a distance of 10 feet from the center. feet (Round to two decimal places as needed.) Find the height of the arch at a distance of 30 feet from the center. feet (Round to two decimal places as needed.) Find the height of the arch at a distance of 50 feet from the center. feet (Round to two decimal places as needed.)Explanation / Answer
standrad equation of parabola is
-x^2 = 4ay
-(90)^2 = 4 * 40 a
a = 8100 / 160
a = 50.625
so,equation becomes
x^2 = - 50.625 * 4 y
plugging x = 10
100 = - 50.625 * 4 y
y = - 0.49 feet
height when distance is 10 feet = 39.51 feet
plugging x = 30
900 = - 50.625 * 4 y
y = -4.44
so, height when distance = 30 feet is 35.56 feet
plugging x = 50
2500 = - 50.625 * 4 y
height when distance is 30 feet is 27.65 feet
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