Answer:
The Order of Operations is very important when simplifying expressions and equations. The Order of Operations is a standard that defines the order in which you should simplify different operations such as addition, subtraction, multiplication and division. This standard is critical to simplifying and solving different algebra problems.
The largest triangle and the triangle whose hypotenuse is x are similar. So:
(21 + 4)/x = x/4
Cross multiply:
x^2 = 100
x = 10
Your answer is incorrect. It should be 10, not 20.
I believe its 132.06, hoped this helped!