Answer:
You use the Pythagorean Theorem or a²+b²=c²
a and b are the two shorter sides, c is the hypotenuse, the longest side.
Step-by-step explanation:
I will do them for you:
12²+16²=20²
144+256=400
400=400
Triangle XYZ is a Right Triangle :)
15²+20²=25²
225+400=625
625=625
Triangle PQR is a Right Triangle :)
