How to prove a polygon is a rectangle?

(if f(x)=4x^2 and g(x)=x+1, find (f o g)(x)

News cameras take an overhead picture of a crowd at an outdoor event journalist then count the total number of people in the picture and use the sample of estimate the total number of people in the crowd this process is an example of

What is the best reason for jacinta to have a savings account in addition to a checking account