127.7=3.14(64-r^2)

Solution for 127.7=3.14(64-r^2) equation:

127.7=3.14(64-r^2)

We move all terms to the left:

127.7-(3.14(64-r^2))=0


We calculate terms in parentheses: -(3.14(64-r^2)), so:

3.14(64-r^2)

We multiply parentheses

-3.14r^2+200.96

Back to the equation:

-(-3.14r^2+200.96)


We get rid of parentheses

3.14r^2-200.96+127.7=0

We add all the numbers together, and all the variables

3.14r^2-73.26=0

a = 3.14; b = 0; c = -73.26;
Δ = b2-4ac
Δ = 02-4·3.14·(-73.26)
Δ = 920.1456
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{920.1456}}{2*3.14}=\frac{0-\sqrt{920.1456}}{6.28}
=-\frac{\sqrt{}}{6.28}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{920.1456}}{2*3.14}=\frac{0+\sqrt{920.1456}}{6.28}
=\frac{\sqrt{}}{6.28}
$