In Fig. 13.12, you see the frame of a lampshade. It is to be covered with a decorative cloth. The frame has a base diameter of 20 cm and height of 30 cm. A margin of 2.5 cm is to be given for folding it over the top and bottom of the frame. Find

Explanation

Diameter of the base of lampshade, d = `20` cm

radius r = `d/2`= `20/2`cm
height = `30` cm

Margin over the top and bottom = `2.5 cm + 2.5 cm = 5cm`
Hence total length of the cloth usedh = 30 cm + 5 cm
h = 35 cm
The cloth required for covering the lampshade = `2pirh` =`2*3.14*10*35=2200cm^2`