10.89=r^2

Solution for 10.89=r^2 equation:

Simplifying
10.89 = r2

Solving
10.89 = r2

Solving for variable 'r'.

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

Add '-1r2' to each side of the equation.
10.89 + -1r2 = r2 + -1r2

Combine like terms: r2 + -1r2 = 0
10.89 + -1r2 = 0

Add '-10.89' to each side of the equation.
10.89 + -10.89 + -1r2 = 0 + -10.89

Combine like terms: 10.89 + -10.89 = 0.00
0.00 + -1r2 = 0 + -10.89
-1r2 = 0 + -10.89

Combine like terms: 0 + -10.89 = -10.89
-1r2 = -10.89

Divide each side by '-1'.
r2 = 10.89

Simplifying
r2 = 10.89

Take the square root of each side:
r = {-3.3, 3.3}