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Question
Curved surface area of a cone is 308 cm2 and its slant height is 14 cm. Find
- radius of the base and
- total surface area of the cone.
`["Assume "pi =22/7]`
Solution
(i) Slant height (l) of cone = 14 cm
Let the radius of the circular end of the cone be r.
We know, Curved surface area of cone = πrl
`(308)cm^2` = `(22/7xxr xx14)cm`
⇒ r = `(308/44)cm` = 7cm
Therefore, the radius of the circular end of the cone is 7 cm.
(ii) Total surface area of cone = Curved surface area of cone + Area of base
= πrl + πr2
= `[308+22/7xx(7)^2]cm^2`
= (308 + 154) cm2
= 462 cm2
Therefore, the total surface area of the cone is 462 cm2.
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