1965=3.14r^2

Solution for 1965=3.14r^2 equation:

Simplifying
1965 = 3.14r2

Solving
1965 = 3.14r2

Solving for variable 'r'.

Move all terms containing r to the left, all other terms to the right.

Add '-3.14r2' to each side of the equation.
1965 + -3.14r2 = 3.14r2 + -3.14r2

Combine like terms: 3.14r2 + -3.14r2 = 0.00
1965 + -3.14r2 = 0.00

Add '-1965' to each side of the equation.
1965 + -1965 + -3.14r2 = 0.00 + -1965

Combine like terms: 1965 + -1965 = 0
0 + -3.14r2 = 0.00 + -1965
-3.14r2 = 0.00 + -1965

Combine like terms: 0.00 + -1965 = -1965
-3.14r2 = -1965

Divide each side by '-3.14'.
r2 = 625.7961783

Simplifying
r2 = 625.7961783

Take the square root of each side:
r = {-25.015918498, 25.015918498}