452.16=4(3.14)r2

Solution for 452.16=4(3.14)r2 equation:

452.16=4(3.14)r2

We move all terms to the left:

452.16-(4(3.14)r2)=0


We calculate terms in parentheses: -(4(3.14)r2), so:

4(3.14)r2

We multiply parentheses

12.56r^2

Back to the equation:

-(12.56r^2)


We get rid of parentheses

-12.56r^2+452.16=0

a = -12.56; b = 0; c = +452.16;
Δ = b2-4ac
Δ = 02-4·(-12.56)·452.16
Δ = 22716.5184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{22716.5184}}{2*-12.56}=\frac{0-\sqrt{22716.5184}}{-25.12}
=-\frac{\sqrt{}}{-25.12}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{22716.5184}}{2*-12.56}=\frac{0+\sqrt{22716.5184}}{-25.12}
=\frac{\sqrt{}}{-25.12}
$