Shape of a bridge is modeled by the equation y=-0.0044x^2+21.3, Find the length of the bridge?( All measurements are in meters).
We assign a coordinate system with ground level y=0, and assume the bridge is level.
The length of the bridge is the distance between the two x-intercepts. We set y=0 and solve for x:
This is the distance from the axis of symmetry (the center of the bridge) to one side of the bridge, so the length of the bridge is approximately 2(69.6)=139.2m