In this video, I will show you how to prove the area of a square using integral calculus. First, you use the area formula under a function, which is equal to the integral from a to b of f(x), where f(x) is a curve of a straight line. Then, we evaluate that integral. This is an important concept to master for Calculus students whether they are taking AP Calculus in high school or they are taking calculus at university.