1. Working Backwards Finding Circumference From Area

2. Finding Area from Circumference: Not Too Difficult We are familiar with the steps for finding Area if we are given the circumference The missing information for solving for the area of a circle is always radius, because Pi is always 3.14

3. Where do we get our radius?

4. So, what if we start with the Area? If we have the area, and we need to find the circumference, what is the missing number that we must find to solve for? We need the Diameter to find circumference, so to find the diameter if we are given Area, we have to work backwards from the area, and find the specific radius. This is harder than it seems. What might be a problem in solving this?

8. Now it’s easy to find the Circumference: if r = 2.5 cm2x r = D 2 x 2.5 cm = D 5 cm = D C= π x D C = 3.14 x 5 cm C = 15. 70 cm