Problem: suppose the area of a circle is 31.4 units squared. about what is the length of the diameter
pi * r^2 = A
3.14 * r^2 = 31.4
(3.14 * r^2) / 3.14 = 31.4 / 3.14
r^2 = 10
4 = sqrt(10)
Ignoring the negative value, r is
approximately 3.16 units.
(If you mean square units, not units squared.)