Algebra 1 I do not understand
posted by Anonymous .
If a circle's circumference is 15 inches, what is its radius?

C = pi * d
15 = 3.14 * d
15/3.14 = d
4.77707 = d
4.77707 / 2 = r
2.388535 = r 
I still don't understand this.

Can you explain the steps in solving this formula?

Please copy and paste the line you don't understand.

C = pi * d
15 = 3.14 * d
15/3.14 = d
4.77707 = d
4.77707 / 2 = r
I apologize, but I do not understand any of them. 
Circumference = pi * diameter
Then I substituted real numbers for the letters. 
How did you know which numbers to use?

Please memorize pi = 3.154
Your problem stated that the circumference is 15.