PLease help with another STUDY question!!?

Question

The radii of 2 circles have the ratio of 1:2, what is the ratio of the area of the larger circle to the smaller circle??

4:1.........thank you so much for the answer!!! I wish I could pick the winner but it wouldn't be fair, so guys go vote!!

Answer 1

Ok, so the radius of the smaller circle can be 1 and the radius of the larger circle can be 2.

For the larger circle:
A = r^2*pi
A = 2^2*pi
A = 4*pi

For the smaller circle:
A = r^2*pi
A = 1^2*pi
A = 1*pi

Ratio of area of large to area of small:
(4*pi) : (1*pi)
You can reduce this by factoring a 1*pi out from both and cancelling them out to get a ratio of --> 4:1

Answer 2

Since the ratio of both circles is 1:2, lets say that the radius of Circle A is x and radius of Circle B is 2x.

So Area of Circle A= Pi * x^2
Area of Circle B= Pi * 4x^2
ratio = Area Circle A/Area Circle B

ratio(areawise)= (Pi * x^2)/ (Pi * 4x^2)

ratio(areawise)= 1/4 or 1:4

Answer 3

4:1

Answer 4

4:1

Answer 5

A=pi r^2
if ratio of r is 1:2, then ratio of r^2 is 1:4

Answer 6

pie*r2 : pie*r2
pie*1^2 : pie * 2^2
so.... ans= 1:4
i guess so