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Simplifying
725.4656 = 4 * 3.14r2
Multiply 4 * 3.14
725.4656 = 12.56r2
Solving
725.4656 = 12.56r2
Solving for variable 'r'.
Move all terms containing r to the left, all other terms to the right.
Add '-12.56r2' to each side of the equation.
725.4656 + -12.56r2 = 12.56r2 + -12.56r2
Combine like terms: 12.56r2 + -12.56r2 = 0.00
725.4656 + -12.56r2 = 0.00
Add '-725.4656' to each side of the equation.
725.4656 + -725.4656 + -12.56r2 = 0.00 + -725.4656
Combine like terms: 725.4656 + -725.4656 = 0.0000
0.0000 + -12.56r2 = 0.00 + -725.4656
-12.56r2 = 0.00 + -725.4656
Combine like terms: 0.00 + -725.4656 = -725.4656
-12.56r2 = -725.4656
Divide each side by '-12.56'.
r2 = 57.76
Simplifying
r2 = 57.76
Take the square root of each side:
r = {-7.6, 7.6}
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