Answer:
5 (rounded)
Explanation:
by using the Pythagorean theorem you can calculate b

here we have a and c
first lets times it by themselves
16 + b^2 = 36
now lets isolate b^2
b^2 = 36-16
= 20
now we have to get rid of the exponent ^2
b = 4.47....
rounding it would be 5!
Hope that helps :>