Geometry

We can write a system of equations as a= pi*r^2 and a+10 = pi*(2r)^2. This is where a is the area and r is the radius. The new radius is 2r. Now we can simplify the second equation to a+10=4(pi*r^2). We can subtract the first equation from the second equation and get 10=3(pi*r^2) and r=sqrt(10/(3*pi)) so 2r = 2sqrt(10/(3*pi)).

You can blame me if I'm wrong but I think this is right.

There is a circle in the coordinate plane. If the radius doubles, the area increases by 10 units. Find the new radius of the circle.

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Radius => r             New radius => 2r

A = r²pi                    A_n = (2r)²pi             (A_n = A + 10)

A_n - A = 10

(2r)²pi - r²pi = 10