In a Right Triangle, Find the Length of the Side $\mathrm{b}=12 \mathrm{~cm}, \mathrm{c}=15 \mathrm{~cm}$

Multiple Choice

In a right triangle, find the length of the side not given. Let c represent the length of the hypotenuse. Give an answer to the nearest tenth if necessary.
- $\mathrm{b}=12 \mathrm{~cm}, \mathrm{c}=15 \mathrm{~cm}$

A) $a=9 \mathrm{~cm}$
B) $a=3 \mathrm{~cm}$
C) $a=81 \mathrm{~cm}$
D) $a=10 \mathrm{~cm}$