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Circumference and area of circles
Circles are everywhere. How can we measure how big they are? Well, we could think about the distance around the circle (circumference). Another option would be to think about how much space it takes up on our paper (area). Have fun!
A circle is at the foundation of geometry and how its parts relate to each other is both completely logical and a wonder.
Radius, diameter, center, and circumference--all are parts of a circle. Let's go through each and make sure we understand how they are defined.
In this example, we solve for the area of a circle when given the diameter. If you recall, the diameter is the length of a line that runs across the circle and through the center.