I need help with this question

Answer:
B (39)
Step-by-step explanation:
Using the Pythagorean theorem (a^2+b^2=c^2) and X=BC length
15^2+36^2=x
225+1296=x
√1521=x
x=39
Answer:
B.
Step-by-step explanation:
The Pythagorean Theorem
a^2+b^2=c^2
In this case it's c^2=a^2+b^2
c^2=15^2+36^2
c^2=225+1296
c^2=1521
c= the square root of 1521
c=39
So...
the length of line segment BC is 39