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Area and circumference of circles
A circle is at the foundation of geometry, and at the foundation of a circle is a special number called Pi. This number allows us to relate the radius, diameter, and circumference of a circle.
Learn how the number Pi allows us to relate the radius, diameter, and circumference of a circle.
Radius, diameter, center, and circumference--all are parts of a circle. Let's go through each and understand how they are defined.
Practice labeling the parts of a circle: radius, diameter, and circumference.
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.
Practice finding the area or circumference of part of a circle.