Question

Find the total surface area of a cone with radius r/2 and slant height 2l

Answer 1

AnswEr :

• Total surface area of cone is πr(r4l)/2 sq units.

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GiveN :

• Slant height = 2l

• Radius = r/2

SoluTion :

By using the formula,

★ Total Surface Area of the cone :

➝ 2π × r( radius + slant height )

➝ 2π × r/2(r/2 + 2l)

➝ πr( r + 4l )/2 sq units

$\therefore$ Total surface area of cone is πr(r4l)/2 sq units.

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Answer 2

$\sf{\bold{\green{\underline{\underline{Given}}}}}$

• radius of cylinder = $\sf\dfrac{r}{2}$
• slant height of cylinder = 2l

$\sf{\bold{\green{\underline{\underline{To\: Find}}}}}$

• Total Surface Area = ???

$\sf{\bold{\green{\underline{\underline{Solution}}}}}$

$\sf{\bold{\red{\boxed{TSA = \pi r ( r + l )}}}}$

$\sf\longrightarrow TSA = \pi\dfrac{r}{2} ( \dfrac{r}{2} + 2l )$

$\sf\longrightarrow TSA = \pi r ( \dfrac{r}{4} + l )$

$\sf\longrightarrow TSA = \pi r ( l + \dfrac{r}{4} )$