Question

A solid cylinder has total surface area 462.Its curved surface area is one third of its total surface area.Find its radius ,height and volume.

Answer 1

total surface area = (2π r h + 2 π r²) = 462 cm²
curved surface area = 2 π r h = 462/3 = 154 cm ²
so,
2π r² = ( 462 - 154)
         =308
⇒ r² = 154 /π
        = 49
⇒ radius = 7 cm
now, 2π r h = 154 cm²
⇒h = 154 /2π r
      = 3.5
height = 3.5 cm