Two cones are similar. The surface area of the larger cone is 65π square inches. The surface area of the smaller cone is 41.6π square inches. The radius of the smaller cone is 6.4 inches. What is the radius of the larger cone?

For similar cones, surface areas scale by the square of the linear scale factor. The area ratio is 65π ÷ 41.6π = 1.5625, so the radius scale factor is √1.5625 = 1.25. The larger radius is 6.4 × 1.25 = 8 inches, so the correct choice is A) 8 inches.

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