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Question
A joker’s cap is in the form of right circular cone of base radius 7 cm and height 24 cm. Find the area of the sheet required to make 10 such caps.
`["Assume "pi=22/7]`
Solution
Radius (r) of conical cap = 7 cm
Height (h) of conical cap = 24 cm
Slant height (l) of conical cap = `sqrt(r^2+h^2)`
= `[sqrt((7)^2+(24)^2)] cm`
= `sqrt (576 + 49) cm`
= `sqrt625 cm`
= 25 cm
Curved surface area of 1 conical cap = πrl
= `(22/7xx7xx25)cm^2`
= 550 cm2
Curved surface area of 10 such conical caps = (10 × 550) cm2 = 5500 cm2
Therefore, the required area of the sheet is 5500 cm2.
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