If it's not what You are looking for type in the equation solver your own equation and let us solve it.
Simplifying
9917.5016 = 4 * 3.14r2
Multiply 4 * 3.14
9917.5016 = 12.56r2
Solving
9917.5016 = 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.
9917.5016 + -12.56r2 = 12.56r2 + -12.56r2
Combine like terms: 12.56r2 + -12.56r2 = 0.00
9917.5016 + -12.56r2 = 0.00
Add '-9917.5016' to each side of the equation.
9917.5016 + -9917.5016 + -12.56r2 = 0.00 + -9917.5016
Combine like terms: 9917.5016 + -9917.5016 = 0.0000
0.0000 + -12.56r2 = 0.00 + -9917.5016
-12.56r2 = 0.00 + -9917.5016
Combine like terms: 0.00 + -9917.5016 = -9917.5016
-12.56r2 = -9917.5016
Divide each side by '-12.56'.
r2 = 789.61
Simplifying
r2 = 789.61
Take the square root of each side:
r = {-28.1, 28.1}
| 15=x+24+x+15 | | 2(5x+5)=13x+4 | | 10130.3936=4*3.14*r^2 | | 2x+218=10x-6 | | .3x-.5(5-x)=1.9 | | 1690.0736=4*3.14*r^2 | | 3-(x*3-2)=-11 | | 30=3y+6 | | 2z^2+90=0 | | 2*-8y=7 | | -3(2x+10)+5=5 | | 8-8k=2(4-5k) | | 9t+8=t+72 | | 5x+4=9x+8 | | 437.2136=4*3.14*r^2 | | -5x^2+5x+8=0 | | .3x-.5(5-5x)=1.9 | | 254.34=4*3.14*r^2 | | 5(2x-3)=2x-(x+3) | | 7p-6=10+11(p+2) | | 8v-5=3+5(v+12) | | x^3-24x+40=0 | | 2x^3-24x+40=0 | | 8x-200=900 | | 3x^2-33x=78 | | 5w-4=11+8(w+4) | | 3x^2-33x=75 | | 98.4-0.365t=102.5 | | 3n-6=9+8(n+3) | | 5y-7=14 | | -1000000x^2-1000000x+90000000=0 | | 5y-y=14 |