Answer:
A)

Explanation:
First you have to plug in the numbers into the Pythagreom Theroum:


(C represents you hypotnuse)
Then you square the numbers:
5 + 16 =

(If your confused why
just came out to be 5, the square and the square root cancel each other out)
Then you add the numbers:
21 =

Then you sqaure root both sides to cancel out the
:
c =
