a. 9.9
b. 10.1
c. 8.9
d. 10.5

Answer:
a should be the length of x.
Step-by-step explanation:
the Pythagorean Theorem can be used to solve this.
a²+b²=c²
If we plug our measurements one by one it's shown that answer choice A is closest to 18.
9.9²+15²=323.01
[tex]\sqrt{323.01}[/tex]=17.97
when rounded this gives us 18.
Hope this helps!
-MoCKEry