Question

4. The volume of a right circular cone is 660 cm and the diameter of its base is 12 cm.
Calculate : (i) the height of the cone;
(ii) the slant height of the cone;
(iii) the total surface area of the cone.​

Answer 1

Step-by-step explanation:

given :- Volume of rt. circular cone = 660 cubic cm

diameter = 12 cm

radius = d/2 = 12/2 = 6 cm

sol.- (i) Volume of Cone =

$\frac{1}{3}\pi r {}^{2}h$

660 = 1/3×22/7×6×6×h

660= 22/7×2×6×h

660×7= 22×12×h

4620=264×h

h= 4620/264

h= 17.5cm

the height of the cone is 17.5 cm.

(ii) The Slant Height of the cone (l)=

$\sqrt{r {}^{2} + h {}^{2} }$

l =

$\sqrt{(6) {}^{2} + (17.5) {}^{2} }$

l =

$\sqrt{36 + 306.25}$

l =

$\sqrt{342.25}$

l = 18.5 cm

hence, The Slant height of the cone is 18.5cm.

(iii) The Total Surface Area of The Cone =

$= \pi r {}^{2} + \pi rl \\ = \pi r(r + l)$

= 22/7 ( 6+18.5)

= 22/7 (24.5)

= 22×24.5/7

= 539/7

= 77

$total \: surface \: area \: of \: the \: cone = 77cm {}^{2}$

thank you.

Answer 2

Step-by-step explanation:

this the answer ...i hope it helps uh...