Question

The volume of a metallic cylindrical pipe is 742 cm. ks length is 14 on and its
external radius is 9 cm. Find its thickness,
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Answer 1

We know that : πR²h - πr²h , Where R represents another radius of pipe and r represent original radius of pipe,Now, We haveπR²h - πr²h = 748 cmπh (R² - r² ) = 748 cm³πh [ ( 9)² - (r²) ] = 748 cm³π.14 [ 81 - r² ] = 748 cm³14 π [ 81 - r² ] = 748 cm³π [ 81 - r² ] = 748 ÷ 14[ 81 - r² ] = 748 ÷ 14 ÷ π[ 81 - r² ] = 748 ÷ 22/7 × 14[ 81 - r² ] = 748 ÷ 44[ 81 - r² ] = 17- r² = 17 - 81- r² = - 64r² = 64 cm ²r = √64 cm•°• r=8cm

r=8cmHence , Required thickness ( radius ) of internal cylindrical pipe is 8 cm