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Circles of diameter 1 inch and 3 inches have the same center. The smaller circle is painted yellow, and the portion outside the smaller circle and inside the larger circle is painted green. What is the ratio of the green-painted area to the yellow-painted area?

a. 1:3
b. 3:1
c. 2:4
d. None of the above

User Miboper
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1 Answer

1 vote

Final answer:

The ratio of the green-painted area to the yellow-painted area is 8:1, calculated by dividing the area of the ring (green region) by the area of the smaller circle (yellow region), resulting in the correct answer being 'None of the above'.

Step-by-step explanation:

The question asks for the ratio of the green-painted area to the yellow-painted area between two concentric circles with diameters of 1 inch and 3 inches, respectively. We start by calculating the area of each circle. The area of a circle is given by πr2, where r is the radius. The radius of the smaller circle is 0.5 inches, and the radius of the larger circle is 1.5 inches.

The area of the yellow-painted circle (smaller circle) is π(0.5)2 = 0.25π square inches. The area of the larger circle is π(1.5)2 = 2.25π square inches. Now, to find the area that is painted green, we subtract the area of the smaller circle from the area of the larger circle: 2.25π - 0.25π = 2π square inches.

To determine the ratio of the green area to the yellow area, we divide the green area by the yellow area:

(2π) / (0.25π) = 8.

Hence, the ratio of the green-painted area to the yellow-painted area is 8:1, which is not listed in the given answer choices, so the correct answer is None of the above.

User PhilG
by
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