A joker's cap is in the form of a cone of radius 7cm and height 24cm. Find the area of the cardboard required to make the cap.
Area of the cardboard required = curved surface area of the cap (or cone ) = πrl
Now,
l=√r2+h2=√72+242=25 cm
Curved surface area = 227×7×25=550 cm2
Therefore, area of the cardboard required = 550 cm2