1. Surface Area Circles

2. Area of Circles How could we find the area of a circle?

3. What if we consider a square?

4. If we found the area of the square, it would be a bit more than the circle inside of it. Extra

5. That means that a circle inside of a square should have a bit smaller area than the square. So, how long is the side of the square? r r

6. The length of one side of a square (with a circle in it) would be 2r r r

7. To figure out the area of the square, (A = 2r x 2r) 2 r A = 2r x 2r A = 2 x 2 x r x r A = 4r²

8. So, in other words, a square with a circle in it would have an area of 4r²…but that is bigger than just the circle. 2 r A = 2r x 2r A = 2 x 2 x r x r A = 4r²

9. So a circle has an area a bit smaller than the square around it. It is actually EXACTLY 3.14 x r² A = πr² A = πr² A = 3.14 x (6cm)² A = 3.14 x 6cm x 6 cm A = 3.14 x 36cm² A = 113.04 cm² R = 6 cm