Question

the slant height of cone is 9m and radius of its base is12m find total surface area of cone​

Answer 1

Answer:

The total surface area of a cone is 792 m².

Step-by-step explanation:

The formula to compute the total surface area of a cone is:

$TSA=\pi rl+\pi r^{2}$

Given:

Slant height = l = 9 m

Radius of base = r = 12 m

Compute the value of TSA as follows:

$TSA=\pi rl+\pi r^{2}\\=(\frac{22}{7}\times 12\times 9)+(\frac{22}{7}\times 12^{2})\\=792$

Thus, the total surface area of a cone is 792 m².

Answer 2

The slant height of cone is 9m and radius of its base is 12m. The surface area of cone is 792m square.

Stepwise explanation is given below:

- It is given that the,

Slant height: l = 9m

Radius: r=12m

- The formula for the total surface area of a right cone is Total Surface Area os equal to Curved Surface Area + base.

- Where The lateral surface area of a cone is the area of the lateral or side surface only.

= (πrl)+(πr^2) .

T.S.A= (πrl)+(πr^2) .

- So, by putting the values of Radius (r) and slant line (l) in the formula-

T.S.A = (π*12*9) + (π*12*12)

T.S.A = (339.29) + (452.38)

T.S.A= (791.68)

Or

- T.S.A= 792m^2