Answer:
25
Step-by-step explanation:
First, you simply square 15, which is 15^2 or 15 times 15, which is 225
Then, you square 20, which is 20^2 or 20 times 20, which is 400
Then, you have 225 + 400 = c^2
You simply add 225 + 400, which is 625
Then, you have 625 = c^2. You're probably wondering what do I do now!
Well, it's simple you square root both sides, to where it looks like this below.
√625 = √c^2
Then, c = 25
Hope This Helped!!!