Question

How would I do number 13?

Answer 1

4x + 3x = 98
7x = 98
x=14

4(14)=56 (one side of the monitor) - so this is a
3(14)=42 (other side of the monitor) - so this is b

diagonal, so use hypotenuse of two sides.

a squared + b squared equals c squared.

56 squared equals 3136
42 squared equals 1764
add those together and take the square root

the diagonal equals 70