A sphere is inscribed inside a cube. The sphere touches each face of the cube at one point. The length of each edge of the cube is 2 inches. We need to find: a. The surface area of the cube. b. The surface area of the sphere (rounded to the nearest hundredth). c. The ratio of the surface area of the cube to the surface area of the sphere (rounded to the nearest hundredth).

GeometrySurface AreaCubeSphereGeometric ShapesRatio
2025/4/14

1. Problem Description

A sphere is inscribed inside a cube. The sphere touches each face of the cube at one point. The length of each edge of the cube is 2 inches. We need to find:
a. The surface area of the cube.
b. The surface area of the sphere (rounded to the nearest hundredth).
c. The ratio of the surface area of the cube to the surface area of the sphere (rounded to the nearest hundredth).

2. Solution Steps

a. Surface area of the cube:
A cube has 6 faces. Each face is a square. The area of one face is the side length squared. Since the side length is 2 inches, the area of one face is 22=42^2 = 4 square inches.
The surface area of the cube is 6 times the area of one face.
SurfaceAreacube=6×(side)2Surface Area_{cube} = 6 \times (side)^2
SurfaceAreacube=6×22=6×4=24Surface Area_{cube} = 6 \times 2^2 = 6 \times 4 = 24 square inches.
b. Surface area of the sphere:
Since the sphere fits snugly inside the cube and touches each face at one point, the diameter of the sphere is equal to the side length of the cube, which is 2 inches. Therefore, the radius of the sphere is r=22=1r = \frac{2}{2} = 1 inch.
The formula for the surface area of a sphere is:
SurfaceAreasphere=4πr2Surface Area_{sphere} = 4 \pi r^2
Substituting r=1r = 1 inch, we have:
SurfaceAreasphere=4π(1)2=4πSurface Area_{sphere} = 4 \pi (1)^2 = 4 \pi
Using the approximation π3.14159\pi \approx 3.14159, we get:
SurfaceAreasphere4×3.14159=12.56636Surface Area_{sphere} \approx 4 \times 3.14159 = 12.56636
Rounding to the nearest hundredth, we get 12.57 square inches.
c. Ratio of the surface area of the cube to the surface area of the sphere:
We need to find the ratio SurfaceAreacubeSurfaceAreasphere\frac{Surface Area_{cube}}{Surface Area_{sphere}}.
Ratio=244π=6πRatio = \frac{24}{4 \pi} = \frac{6}{\pi}
Using the approximation π3.14159\pi \approx 3.14159, we get:
Ratio63.141591.909859Ratio \approx \frac{6}{3.14159} \approx 1.909859
Rounding to the nearest hundredth, we get 1.
9
1.

3. Final Answer

a. 24 in2in^2
b. 12.57 in2in^2
c. 1.91

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