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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!
Learn how the number Pi allows us to relate the radius, diameter, and circumference of a circle.
Practice finding the radius, diameter, or circumference of a circle. For example, if the diameter of a circle is 16, what is its 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.
Find the areas of shaded regions which are combinations of squares, triangles, and circles.
Sal finds the radius and diameter of a circle given the circumference.
You'll be given the circumference or the area of a circle, and it will be up to you to figure out the radius or the diameter.
Using triangles to create an informal argument for the area of a circle formula.