
Ian H. answered 03/31/21
Aerospace Engineer, United States Marine, SAT/ACT Tutor, Mathematics T
You know the formula for the area of the circle is ACircle = π*r2. We also know that the diameter of a circle is twice its radius. We can write the radius of the big circle as R = D/2 = 8/2 = 4 and the radius of the smaller circle as r = d/2 = 4/2 = 2.
Now we can calculate the areas of the circles.
ALarge = π*R2 = π*(4)2 = 16π
ASmall = π*r2 = π*(2)2 = 4π
We can write the ratio as ASmall:ALarge = 4π:16π
This ratio can be simplified by dividing it by a factor of 4π on each side.
Your final answer will be 1:4 or in words, the circle with the larger diameter has an area that is four times larger than the area of the circle with the smaller diameter.
Hope this helps!

Ian H.
Anytime!04/01/21
Rylie A.
Thank you so much!! It helped a lot!!03/31/21