Question

find thr curved surface area of a cone if its diameter of base is 24cm and start height is 21cm​

Answer 1

Answer:

Slant height of cone is l = 21 m

Diameter of its base is d = 24 m

So, radius of its base is r = d/2 = 12 m

Now, the total surface area of cone is

area = πrl + πr2

area = π(rl + r2)

area = π(12×21 + 122 )

area = π(252 + 144)

area = (22/7) ×396

So total area is = 1244.5714 m2

Answer 2

Given:

• diameter of the cone = 24cm
• slant height of the cone = 21cm

To Find:

curved surface area of the cone

Solution:

• diameter of cone = 24cm

☆ radius of the cone = $\sf{\frac{24}{2} = 12cm}$

• slant height (l) of the cone = 21cm

We Know That:

${ \boxed{ \orange{ \sf{ \: total \: surface \: area \: of \: cone \: = \pi r(l + r)}}}}$

so, putting the values:

$\implies\sf{ \frac{22}{7} × 12 × (12 + 21)cm²}$

$\implies\sf{ \frac{22}{7} × 12 × 33cm²}$

$\implies\sf{ 1244.57 cm²}$

Hence,

curved surface area of the cone is 1244.57cm²

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☆ Formula Related To Cone ☆

⊱ surface area of cone = πrl + πr²

⊱volume of cone = $\sf{\frac{1}{3}πr²h}$

⊱ curved surface area of cone = πrl