the total surface area of a hollow cylinder which is open from both sices is 4620sq.cm area of base ring is 115.5sq.cm and height 7 cm .find the thickness of the cylinder.
the total surface area of a hollow metal cylinder open at both ends of external radius 8 cm and height 10cm is 338p cm. taking r to be inner radius obtain an equation in r and use it to obtain the thickness of the metal in the cylinder.
a cylindrical vessel without lid hasw to be tin coated on its both sides .if the radius of base i9s 70cm and height 1.4m calculate the cost of tin coating at the rate of rs3.50 per 1000cm2
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SA 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 = 8 – r
= 8 – 5 = 3 cm
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