Area of a circle is directly proportional to the square of radius of the circle while the circumference is proportional to the radius of the circle. This means that if the radius of a circle is increased x times, then its area will be increased to x^2 times the original area, and the circumference will increase to x times the original circumference.
Thus when the radius is doubled, or in other words if radius mad 2 time the original radius, the area of circle will become 2^2 = 4 time the original area. The circumference will become 2 times the original circumference.
We can calculate exact area and circumference of a circle from its radius using the following equations:
Area of circle = (pi/4)*r^2
Circumference of circle = 2*pi*r
Where r is the radius of the circle.
I know this is a lot, sorry.
Answer:
x = -1, x = 1
Step-by-step explanation:
Factor the equation. (It's a difference of squares, so we know the form will be (a-b)(a+b).)

Test this by FOILing it out, if you're unsure. This is something it can be good to memorize!
Set it equal to 0.

Separate the two parenthetical expressions by the Zero Product Property.

Solve for x!

100 * pi = pi * r^2
Pi cancels on both sides of the equation
So... 100= r^2
= radius is 10
B is the answer!
Explanation:
m^2 n^2 fits into both, you can take m^2 n^2 out of it both.
m is a common factor since you can take m out of both but it’s not the greatest common factor.
2n & 2m wouldn’t even be a common factor bc there is no 2n or 2m in neither.