Question

total surface area of cone with radius r/3 and slant height is 3 l is​

Answer 1

TSA of a cone is =πr(l+r)

=π×r/3(3l+r/3)

=18π+9l+r^2/9

Answer 2

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

Step-by-step explanation:

Given : Cone with radius $\frac{r}{3}$ and slant height is $3l$.

To find : The total surface area of cone ?

Solution :

Radius is  $\frac{r}{3}$ .

Slant height is $3l$.

The total surface area of cone is given by,

$TSA=\pi r(r+l)$

Substitute the values,

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

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

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

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

#Learn more

What is the total surface area of a cone whose radius is r/2 and slant height is 2L

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