Use the Accompanying Diagram, Which Contains Two Similar Triangles

Multiple Choice

$\begin{array}{|l|c|c|}\hline {\text { Item }} & \text { Quantity Needed } & \text { Cost } \\\hline 8 \text { Spark plugs } & 1 \text { set } & \$ 31.84 \\\text { Spark plug wires } & 1 \text { set } & \$ 73.92 \\\text { Distributor cap } & 1 & \$ 24.16 \\\text { Rotor } & 1 & \$ 9.10 \text { each } \\\text { Labor } & \text { Flat rate } & \$ 80.00 \\5 \% \text { sales tax on } & & \\\text { parts only } & & \\\hline\end{array}$ Use the accompanying diagram, which contains two similar triangles. In the larger triangle, side A is 8 feet and side C is 20 feet. In the smaller triangle, side a is 3 feet. Find, in feet, side c.

A) 7 1/2
B) 8
C) 9
D) 10