You add all those number together then divide the number you got by how many numbers there are and that's your answer, 61.1
edit : dont listen to me I didnt see the numbers 64 and 65, im sorry
This is called the Pythagorean theorem : a ² + b ² = c ². You can substitute any of the variable with any of the known numbers and then you all you have to do is isolate the variable. I hope that helps!!
Why do math got to be so complicated
