1. The Circumference of a Circle
How many times does the diameter fit around the circumference? Choose your number. 1 1½ 2 2½ 3 3½ 4 d 1 2
Diameter(d)
Circumference (C)
In terms of the radius C = 2πr 3

2. It’s the same for all circles!

3. The Area of a Circle
4 Sectors

4. 8 Sectors

5. 16 Sectors

6. 32 Sectors

7. As the number of sectors  , the transformed shape becomes more and more like a rectangle.
What are the dimensions of this rectangle?
What is its area in terms of the radius?
Remember
C = 2πr
A = πr x r = πr2