A = pi * r^2
C = pi * d
Which value for the radius fits both formulas?
If the number of square inches in the area of a circle is equal to the number of inches in its circumference, the diameter of the circle is
A. 4 inches
B. 3 inches
C. 1 inch
D. NONE
2 answers
so you want to set the area equal to the circumference ..
πr^2 = 2πr
r^2 - 2r = 0
r(r-2) = 0
r = 0 , the trivial case
or
r = 2
so the diameter is 4 inches
πr^2 = 2πr
r^2 - 2r = 0
r(r-2) = 0
r = 0 , the trivial case
or
r = 2
so the diameter is 4 inches