algebra
posted by Jamie .
A satellite dish has a parabolic cross section and is 6 ft deep. The focus is 4 ft from the vertex. Find the width of the satellite dish at the opening. Round your answer to the nearest foot.
Thank you

from y^2 = 4px
the parabola has equation:
y^2 = 16x
at its widest point, x = 6
y^2 = 16(36) = 576
y + ±24
so the width = 48 ft