Question

You are tasked with analyzing a design that has been drawn for a bridge over an existing two-lane road. The arch over the road is in the shape of a half-ellipse that is 40 feet wide at the base of the arch and it is 15 feet tall at the center of the arch. The bridge must have a 13-foot clearance for vehicles on the road. The 22-foot-wide road is centered directly beneath the highest point of the arch. a) the semi-truck will NOT be able to pass under the bridge,so it is time to make an adjustment. You will need to modify the design of the bridge. Keep the arch shape as half an ellipse, and the base as 40 feet wide. You may adjust the bridge’s arch up to 18 feet above the center line of the two-lane road below, but no more than that because of restrictions concerning the road crossing over the bridge. Give a new equation for the ellipse that represents your modified design.

Answer 1

We are asked to determine the equation of an ellipse that has a base of 40 feet and a height of 18 feet. This can be visualized in the following diagram:

The general form of the equation of an ellipse is:

`(x^2)/(a^2)+(y^2)/(b^2)=1`

We have set the origin of the coordinate system to be in the middle of the ellipse. The value of "a" is the x-intercept of the ellipse and the value of "b" is the y-intercept of the ellipse. Therefore, the equation is:

`(x^2)/((20)^2)+(y^2)/((9)^2)=1`

Now, we solve the squares:

`(x^2)/(400)+(y^2)/(81)=1`

And thus we have determined the equation of the ellipse.