MEDAL +FAN, HELP
In the figure, OA = r and OC = R.

The sector COB is cut from the circle with center O. The ratio of the area of the sector removed from the outer circle to the area of the sector removed from the inner circle is

Question

MEDAL +FAN, HELP 
In the figure, OA = r and OC = R.

The sector COB is cut from the circle with center O. The ratio of the area of the sector removed from the outer circle to the area of the sector removed from the inner circle is

alexa · Answer

https://cdn.ple.platoweb.com/EdAssets/2ef79b27f9644280bb239a89f78b3aab?ts=635406317656130000

alexa · Answer

A.  R^2/r^2
B.  R/r
C.  (R^2-r^2)/r^2
D.  1

mathstudent55 · Answer

Do you know how to find the area of a sector of a circle?

alexa · Answer

no

mathstudent55 · Answer

$A_{sector} = \dfrac{n}{360^\circ} \times \pi r^2$

The area of a sector of a circle is a fraction of the total area of the circle.
n is the angle of the sector.

mathstudent55 · Answer

In your case both the large sector and the small sector use the same angle. 
The angle is unknown, so call the angle measure n.
Use the formula above, and write the area of each sector using n for the angles, and r for the small radius and R for the large radius.

mathstudent55 · Answer

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