153.86=2.14r^2

Solution for 153.86=2.14r^2 equation:

153.86=2.14r^2

We move all terms to the left:

153.86-(2.14r^2)=0

We get rid of parentheses

-2.14r^2+153.86=0

a = -2.14; b = 0; c = +153.86;
Δ = b2-4ac
Δ = 02-4·(-2.14)·153.86
Δ = 1317.0416
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{1317.0416}}{2*-2.14}=\frac{0-\sqrt{1317.0416}}{-4.28}
=-\frac{\sqrt{}}{-4.28}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{1317.0416}}{2*-2.14}=\frac{0+\sqrt{1317.0416}}{-4.28}
=\frac{\sqrt{}}{-4.28}
$