# Quadratic formula Word problems

By D. Moseley

We can use the vertex formula to find the maxim/minimum height of a parabola. It can be used to determine the height in real word problems

## The New River Gorge Bridge in west Virginia is the world's largest steel single arch bride. You can model the arch with the function y=-0.000498x^2 +0.847x, where x and y are in feet. How high above the river is the arch if from the base of the bridge to the ground is 516 feet?

Sketch it!

Solve for your vertex.

You then get 360 feet for the height of your parabola. When you look back at your original problem It ask you how high from the river is the maximum height of the arch. To do this you must add your answer (360) to 516.

Voila, there you have it!