Question

The slant height of a cone is 8.45cm

and the diameter of the base is 14cm.
Calculate, three significant figures, the
curved surface area of the cone (Take
= 22÷7
​

Answer 1

`\bf \underline{ \underline{Given : }}`

• Slant height,l = 8.45 cm

• Diameter of base = 14 cm

`\bf \underline{ \underline{To \: be \: calculated : }}`

Calculate the curved surface area of the cone .

`\bf \underline{ \underline{Formula \: applied : }}`

Curved surface area of cone = πrl

`\bf \underline{ \underline{Solution : }}`

First of all,

Radius = Diameter/2

=> Radius,r = 14/2

=> Radius,r = 7 cm

Now,

`\sf{Curved \: surface \: area \: of \: cone =\pi rl}`

`\sf \: \implies \: (22)/( \cancel7) * \cancel7 * 8.45`

`\sf\implies22 * 8.45`

`\sf \implies 185.9 \: {cm}^(2)`

Hence,the Curved surface area of cone is 185.9 cm².