300=2(3.14)r2

Solution for 300=2(3.14)r2 equation:

300=2(3.14)r2

We move all terms to the left:

300-(2(3.14)r2)=0


We calculate terms in parentheses: -(2(3.14)r2), so:

2(3.14)r2

We multiply parentheses

6.28r^2

Back to the equation:

-(6.28r^2)


We get rid of parentheses

-6.28r^2+300=0

a = -6.28; b = 0; c = +300;
Δ = b2-4ac
Δ = 02-4·(-6.28)·300
Δ = 7536
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{7536}=\sqrt{16*471}=\sqrt{16}*\sqrt{471}=4\sqrt{471}$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{471}}{2*-6.28}=\frac{0-4\sqrt{471}}{-12.56}
=-\frac{4\sqrt{471}}{-12.56}
=-\frac{\sqrt{471}}{-3.14}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{471}}{2*-6.28}=\frac{0+4\sqrt{471}}{-12.56}
=\frac{4\sqrt{471}}{-12.56}
=\frac{\sqrt{471}}{-3.14}
$