A rectangular wooden block measures 20 cm by 14 cm by 5 cm. A cylindrical hole of radius 3.5 cm is drilled straight through the 5 cm thickness. Find the volume of wood left, in cubic centimetres. (Take π = 22/7.)

Question

Accepted Answer

1207.5. Block = 20 × 14 × 5 = 1400 cm³. The hole is a cylinder of radius 3.5 cm and height equal to the 5 cm thickness: \π r^2 h = 22/7(12.25)(5) = 192.5 cm³. Wood left = 1400 − 192.5 = 1207.5 cm³. 1592.5 adds the hole instead of subtracting it; 1400 forgets the hole; 630 uses the diameter 7 cm as the radius.

A rectangular wooden block measures 20 cm by 14 cm by 5 cm. A cylindrical hole of radius 3.5 cm is drilled straight through the 5 cm thickness. Find the volume of wood left, in cubic centimetres. (Take π = 22/7.)

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