Question

a pen holder made up of cardboard has the shape of a cylinder with a base of radius 3cm and height 10.5 cm. Find the area of cardboard requested to make 35 such pen holders.

Answer 1

Curved Surface area of 1 pen stand = 2×pie×r×h
= 2×22/7×3x10.5
= 2×22×3×1.5
= 198

Area of cardboard required for 35 cardboard = 198×3
= 594

Hope it helps!!

Answer 2

Area of one holder
$\pi \: {r}^{2} h$
= 22/7 * 3*3*10.5
=296.99

thus for 35 holders

35*296.99=10394.65