A Solar Oven Uses a Parabolic Reflector to Focus the Sun's

Multiple Choice

A solar oven uses a parabolic reflector to focus the sun's rays at a point 7 inches from the vertex of the reflector (see figure) . L = 7 inches
Write an equation for a cross section of the oven's reflector with its focus on the positive y axis and its vertex at the origin.

A) $y = 28 x ^ { 2 }$
B) $y = \frac { 1 } { 7 } x ^ { 2 }$
C) $x ^ { 2 } = 28 y$
D) $y ^ { 2 } = 7 x$
E) $x ^ { 2 } = 7 y$