9+81r^2=10

Solution for 9+81r^2=10 equation:

Simplifying
9 + 81r2 = 10

Solving
9 + 81r2 = 10

Solving for variable 'r'.

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

Add '-9' to each side of the equation.
9 + -9 + 81r2 = 10 + -9

Combine like terms: 9 + -9 = 0
0 + 81r2 = 10 + -9
81r2 = 10 + -9

Combine like terms: 10 + -9 = 1
81r2 = 1

Divide each side by '81'.
r2 = 0.01234567901

Simplifying
r2 = 0.01234567901

Take the square root of each side:
r = {-0.111111111, 0.111111111}