Question

The difference between the inner and outer surface of a cylendrical pipe is 88sq cm.if the height of the cylendrical pipe is 14cm and volume is 176 cube cm,find the inner and the outer radii

Answer 1

h = 14cm
V = 176 cm³
⇒ πr²h = 176
⇒ r² = 176/(14π) = 4
⇒ r = √4 
⇒ r = 2cm

difference between the inner and outer surface of a cylendrical pipe is 88sq cm
$2 \pi h(r_o-r_i)=88\\ \\ \Rightarrow (r_o-r_i) = \frac{88}{2 \times 14 \times 3.14} \\ \\ \Rightarrow (r_o-r_i) =1\\ \\ \Rightarrow r_o=1+r_i=1+2\\ \\ \Rightarrow r_o=3\ cm$

Inner radius = 2cm
Outer radius = 3cm