Answer:
So we have to remember that the formula for the area of a circle is C=2πr or πd, which mean the same thing, 2 x r = d, if it makes sense.
I would use C=πd, just because it would make the process less confusing
Lets use 3.14 for π
C=πd
C/π = d
d/2 = r
78.5 = (3.14)(d)
78.5/3.14 = d
25.0 = d
25/2 = 12.5=r
