Can someone plz help?

The length of the third side is 75.

Step-by-step explanation:

You have to use pythagorean theorem to solve this problem.  The pythagorean theorem is:  a² + b² = c².

In this case, the third side is equal to c.  Side c is always opposite of the right  angle.  It doesn't matter whether 60 or 45 is a or b because you are going to add them together anyways.

60² + 45² = c²

c² = 5625

c = 75 You get 75 by taking the square root of 5625.