Question

what is the total surface area of a cone whose r = r/3 and slant height= 3L​

Answer 1

Answer:

The total surface are of the cone is \frac{\pi r(r+9l)}{9} 9πr(r+9l)

Given : Cone with radius \frac{r}{3} 3r

and slant height is 3l3l .

To find : The total surface area of cone ?

Solution :

Radius is \frac{r}{3} 3r

Slant height is 3l3l .

The total surface area of cone is given by,

TSA=\pi r(r+l)TSA=πr(r+l)

Substitute the values,

TSA=\pi \frac{r}{3}(\frac{r}{3}+3l)TSA=π 3r ( 3r +3l)

TSA=\pi \frac{r}{3}(\frac{r+9l}{3})TSA=π 3r( 3r+9l )

TSA=\frac{\pi r(r+9l)}{9}TSA= 9πr(r+9l)

Therefore, the total surface are of the cone is \frac{\pi r(r+9l)}{9} 9πr(r+9l)

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Step-by-step explanation:

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