A hollow pipe is 1.2 meters long and has an inner radius of 3 cm and outer radius of 4 cm. Find the volume of material used in the pipe.
Show answer & explanation
Correct answer: B
Explanation
Given:
Length = 1.2 m = 120 cm
Outer radius (R) = 4 cm
Inner radius (r) = 3 cm
According to the formula:
Volume of a hollow cylinder = πh(R² − r²)
Volume = π × 120 × (4² − 3²)
= π × 120 × (16 − 9)
= π × 120 × 7
= 840π
Volume of the metal used = 840π cm³