Question

find the total surface area of a cone if it's slant height is 21 metre and diameter of its base is 24 metre​

Answer 1

Answer:

Answer: The total surface area the cone is 1244.57 m²

Step-by-step explanation:

Given : slant height of cone ;l = 21m

Diameter of cone = 24m

therefore radius ; r= 12 m

as we know the total surface area of a cone is

Hence, the total surface area the cone is 1244.57 m²

Answer 2

Given:-

• Slant height of cone = 21 m.
• Base diameter of cone = 24 m.

To find:-

• Total surface area of cone.

Solution:-

We know that,

$\large \boxed{ \sf Total\: surface\:area \:of\:cone= \pi {r}^{2} + \pi rl}$

In which,

• r is Radius of cone.
• l is slant height of cone.

l = Slant height of cone = 21 m.

r = 24/2 = 12 cm.

Put all values in formula,

$\implies \sf \dfrac{22}{7} \times 12 \times 12 + \dfrac{22}{ \cancel{7}} \times 12 \times \cancel{21}$

$\implies \sf \dfrac{3168}{7} + 792$

$\implies \sf 452.571 + 792$

$\implies \sf 1244.571$

Therefore,

Total surface area of cone is 1244.571 cm².