What is the total surface area of a cone if its diameter = $1$ ft and slant height = $12$ ft. (use $π = 3.14$ ).
$18.625 {f t}^{2}$
$19.625 {f t}^{2}$
$11.625 {f t}^{2}$
$19.625 f t$

Question

What is the total surface area of a cone if its diameter = $1$ ft and slant height = $12$ ft. (use $π = 3.14$ ).
$18.625 {f t}^{2}$
$19.625 {f t}^{2}$
$11.625 {f t}^{2}$
$19.625 f t$

Toppr Admin · Accepted Answer

Given- diameter- d-1 ft-Then- radius r-d2-12 ft-Therefore- surface area of a cone-xA0-x3C0-rs-x3C0-r2-3-14-xD7-12-xD7-12-3-14-xD7-12-xD7-12-18-84-0-785-19-625-xA0-ft2-Hence- option C is correct-

What is the total surface area of a cone if its diameter =1 ft and slant height = 12 ft. (use π=3.14).18.625ft219.625ft211.625ft219.625ft

Given, diameter, d=1 ft.Then, radius r=d2=12 ft.Therefore, surface area of a cone =πrs+πr2=3.14×12×12+3.14×12×12=18.84+0.785=19.625 ft2.Hence, option C is correct.

What is the total surface area of a cone if its diameter = $1$ ft and slant height = $12$ ft. (use $π = 3.14$ ).
$18.625 {f t}^{2}$
$19.625 {f t}^{2}$
$11.625 {f t}^{2}$
$19.625 f t$

Given, diameter, $d = 1$ ft.
Then, radius $r = \frac{d}{2} = \frac{1}{2}$ ft.

Therefore, surface area of a cone $= π r s + π r^{2}$
$= 3.14 \times \frac{1}{2} \times 12 + 3.14 \times \frac{1}{2} \times \frac{1}{2}$
$= 18.84 + 0.785$
$= 19.625 {f t}^{2}$ .

Hence, option $C$ is correct.