Question

The total surface area of a hollow metal cylinder, open at both ends of externa
radius 8 cm and height 10 cm is 338 p cm2. Taking r to be inner radius, obtain a
equation in rand use it to obtain the thickness of the metal in the cylinder.​

Answer 1

Step-by-step explanation:

Surface area of the hollow cylinder = 338π, cm2

2π(8)10 + 2π(r)10 + 2[π(8)2 – π(r)2] = 338π

⇒ 160 + 20r + 2(64 – r2) = 338

⇒   -2r2 + 20r – 50 = 0

⇒   r2 – 10r + 25 = 0

⇒     (r – 5)2  = 0

⇒   r = 5

∴   Thickness of the metal in the cylinder = 8 – r

= 8 – 5 = 3 cm

hope it helps