### Area of a Circle - YourTeacher.com - Math Help

For a complete lesson on area of a circle, go to http://www.yourteacher.com - 1000+ online math lessons featuring a personal math teacher inside every lesson! In this lesson, students learn that the formula for the area of a circle is pi times radius squared, so the area of a circle that has a radius of 5 inches is pi times 5 squared, or 25 pi square inches. And since pi = 3.14, 25 pi square inches can also be written as 25 times 3.14, or 78.5 square inches. Note that the radius of a given circle is half the diameter of the circle. So to find the area of a circle with a given diameter, first find the radius of the circle by dividing the diameter by 2.

Length:
02:38