I have no idea what im doing, can someone please help me? ASAP!!!! Use the pythagorean theorem to find the missing slide.

Answer:
1. b=√56
Step-by-step explanation:
1. Pythagorean therom states a²+b²=c² and in number 1 we are given the c or the hypotenuse so plugging in the values we know 13²+b²=15²
which equals 169+b²=225 subtract 169 from both sides and we get b²=56
square root both sides and we get b=√56