Wednesday, June 13, 2012


Formula for Diameter is D=2r
        eg. Your radius is 4. If you multiply it by 2. so 4x2, it will equal to so that's your diameter.
Formula for Radius is R=D 
         eg. Your diameter is 6. If you divide it by 2, so 6 ÷ 2. It will equal to 3 so that's your radius 
Formula for Circumference are C=2πr or C=πd
         eg. The diameter is 6, what is the circumference? you can do this 2 ways. 
 1) Using the diameter. 6xπ = 18.84
2) Using the radius. This one has an extra step. First you have to find the radius. 
6÷2=3 Then you do the formula. 3 x 2 x 3.14 = 18.84 
Formula for Area of Circle is A=πr^2            
               eg. The diameter is 8 what is the area?
1) You have to find the radius so 8 ÷ 2 = 4 
2) use the formula so 3.14 x 4 ^2 (squared) = 50.24


  1. Nice, post Jessica. I like how you showed how to do it step by step and made it easy to follow. I also like how you made the formulas stand out.

  2. Good job Jess! I like how you explained each step and how you made the formaulas stand out, like what Angela said.