Aparabolic lattice arch is 8 feet high at the vertex. at a height of 4 feet, the width of the lattice is 4 ft. how wide is the lattice arch at ground level?

The arch is in the shape of an inverted parabola. The equation of the arch is found as follows:

Substituting the values at a height of 4 ft, we get:
4 = -4a + 8
a = 1
At ground level y = 0:


therefore the width of the arch at ground level is: