Hi! can you help me please with this? and process pls?

Show your workcan a right triangle have this sides? *how to prove it without using the pythagorean theorema*

Carlos spent 1 1/4 hours doing his math homework he spent 1/4 of his time practicing his multiplication facts how many hours to carlos been practicing his multiplication facts

The sum of 5consecutive even numbers is 100. what is the first number in this sequence?