Answer:
C) 25
Step-by-step explanation:
First, solve for the height (red dotted line) using the Pythagorean theorem 9²+b²=15²
81+b²=225
b²=225-81
b²=12
Then set up a ratio.
x/12=9/15
simplify
x/12=3/5
cross-multiply
3x=60
x=20
This gives us the base. Now we can solve for x using the Pythagorean theorem again.
20²+15²=x²
400+225=x²
625=x²
√x²=√625
x=25
