Okay so, you use A^2+B^2=C^2
A is 28 (side.) And C (hypotenuse) is 53.
So, 28^2+B^2=58^2 (^2 is squared)
We dont know what the other side is, so we keep it “B.”
28 squared is 784. 53 squared is 2,809.
So now, we take away ^2 since it was already squared. 784+B^2=2,809
Now, we subtract 784 from both sides
784+B^2=2,809
-784 -784
B^2= 2,025
Then you do the opposite of squaring, you square root
45. the missing side is 45