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Simplifying
1358.4896 = 4 * 3.14r2
Multiply 4 * 3.14
1358.4896 = 12.56r2
Solving
1358.4896 = 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.
1358.4896 + -12.56r2 = 12.56r2 + -12.56r2
Combine like terms: 12.56r2 + -12.56r2 = 0.00
1358.4896 + -12.56r2 = 0.00
Add '-1358.4896' to each side of the equation.
1358.4896 + -1358.4896 + -12.56r2 = 0.00 + -1358.4896
Combine like terms: 1358.4896 + -1358.4896 = 0.0000
0.0000 + -12.56r2 = 0.00 + -1358.4896
-12.56r2 = 0.00 + -1358.4896
Combine like terms: 0.00 + -1358.4896 = -1358.4896
-12.56r2 = -1358.4896
Divide each side by '-12.56'.
r2 = 108.16
Simplifying
r2 = 108.16
Take the square root of each side:
r = {-10.4, 10.4}
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