Question

if the area of circle is halved and the radius is decreased by n then the radius will be

Answer 1

Let the initial radius of the circle be r and area be \(\pi r^2\)
let the new radius be \(r_1\)
\(r_1=r-n\)
new area is \(\Large\frac{\pi r^2}{2}\)
\(\Large\frac{\pi r^2}{2}=\pi {r_1}^2\)
\(r^2=2{r_1}^2\)
\(r^2=2(r-n)^2\)
solve for r.Does that help?

Answer 2

I wonder if n was a factor (such as 0.7) rather than a number to be subtracted.

Answer 3

Making the question r2 = n r1 when A2 = (1/2) A1

Answer 4

Glad to have helped.

Answer 5

thanks I need the answer as n(2+root2)

Answer 6

if so then u need to solve the equation I gave.
\(r^2=2(r^2-2rn+n^2)\)
\(r^2=2r^2-4rn+2n^2\)
\(r^2-4rn+2n^2=0\)
use
\[r=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\]
here
b=-4n
c=2n^2
a=1