400.9466=3.14*r^2

Solution for 400.9466=3.14*r^2 equation:

Simplifying
400.9466 = 3.14r2

Solving
400.9466 = 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.
400.9466 + -3.14r2 = 3.14r2 + -3.14r2

Combine like terms: 3.14r2 + -3.14r2 = 0.00
400.9466 + -3.14r2 = 0.00

Add '-400.9466' to each side of the equation.
400.9466 + -400.9466 + -3.14r2 = 0.00 + -400.9466

Combine like terms: 400.9466 + -400.9466 = 0.0000
0.0000 + -3.14r2 = 0.00 + -400.9466
-3.14r2 = 0.00 + -400.9466

Combine like terms: 0.00 + -400.9466 = -400.9466
-3.14r2 = -400.9466

Divide each side by '-3.14'.
r2 = 127.69

Simplifying
r2 = 127.69

Take the square root of each side:
r = {-11.3, 11.3}