A solid hemisphere of radius 4.2 cm has a conical hole of the same radius drilled into its flat face to a depth of 3 cm. Find the volume of the solid that remains, in cubic centimetres, correct to two decimals. (Take π = 22/7.)

Question

Accepted Answer

99.79. Hemisphere = 2/3\π r^3 = 2/3 × 22/7 × 74.088 = 155.23 cm³. Cone removed = 1/3\π r^2 h = 1/3(55.44)(3) = 55.44 cm³. Remaining = 155.23 − 55.44 = 99.79 cm³. 210.67 adds the hole instead of subtracting it; 155.23 forgets the hole; 255.02 uses 4/3\π r^3 for the hemisphere, doubling it.

A solid hemisphere of radius 4.2 cm has a conical hole of the same radius drilled into its flat face to a depth of 3 cm. Find the volume of the solid that remains, in cubic centimetres, correct to two decimals. (Take π = 22/7.)

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