Find the circumference use
3 1/7 for pi age 7th grade. 

Hi, The mathematical fact you need is that if you have a circle, no matter how large or small, the circumference divided by the diameter is always pi. Said another way
In your first example the radius is 28 feet. Since the diameter is twice the radius, the diameter is 56 feet. Thus the circumference is given by
For the second problem the diameter is 98 feet so
Penny 

