Area of Circles
Area of a circle:
Draw a circle either freehand or go to GeoGebra to create a circle, cut the circle into two semicircles. How could you make the semi circles form a parallelogram? A rectangle? What if you were to divide the circle in quarters or eighths?
Think about how the area of circle is related to the area of a parallelogram. See the video below for a complete explanation.
Watch the video below. How did your thinking compare to the video? Return to this page by using the back arrow.
Area of a circle, how to get the formula.
You can also find the circumference of the circle by using the formula 2πr so you can also find the length of a part of a circle called an arc. Watch the following video to review finding the length of an arc.