A hollow iron pipe is 21 cm long and its external - Wikitechy https://www.wikitechy.com/interview-questions/tag/a-hollow-iron-pipe-is-21-cm-long-and-its-external/ Interview Questions Tue, 07 Sep 2021 05:22:20 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 https://www.wikitechy.com/interview-questions/wp-content/uploads/2025/10/cropped-wikitechy-icon-32x32.png A hollow iron pipe is 21 cm long and its external - Wikitechy https://www.wikitechy.com/interview-questions/tag/a-hollow-iron-pipe-is-21-cm-long-and-its-external/ 32 32 Determine the metal required to make a 21 m long pipe if its inner and outer diameter is 12 m and 10 m respectively ? https://www.wikitechy.com/interview-questions/geometry/determine-the-metal-required-to-make-a-21-m-long-pipe-if-its-inner-and-outer-diameter-is-12-m-and-10-m-respectively/ https://www.wikitechy.com/interview-questions/geometry/determine-the-metal-required-to-make-a-21-m-long-pipe-if-its-inner-and-outer-diameter-is-12-m-and-10-m-respectively/#respond Tue, 17 Aug 2021 15:58:43 +0000 https://www.wikitechy.com/interview-questions/?p=1811

Determine the metal required to make a 21 m long pipe if its inner and outer diameter is 12 m and 10 m respectively ?

A. 725 m3

B. 2534 m3

C. 2843 m3

D. 2647 m3

Answer : A. 725 m3

Explanation:

Find the volume with diameter = 12 m

Radius = Diameter ÷ 2
Radius = 12 ÷ 2 = 6 m
Volume = π * r2 * h
Volume = π * (6)2 * 21
V1 = 2,375 m3

Find the volume with diameter = 10 m

Radius = Diameter ÷ 2
Radius = 10 ÷ 2 = 5 m
Volume = π * r2 * h
Volume = π * (5)2 * 21
V2 = 1650 m3

Find the volume of the metal used:

Volume = V1 – V2
= 2,375 – 1650
Volume = 725 m3

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