Question

Find the total surface area of a cone, if its slant height is 21 m and diameter of its base

is 24 m.​

Answer 1

Step-by-step explanation:

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Answer 2

✪ Given :-

• Slant height of cone = 21 m
• Diameter of the base = 24 m

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✪ To Find :-

• The Total Surface Area of a Cone

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✪ Solution :-

Formula to find T.S.A of a Cone → πr (r + L)

Here r is the radius and L is the slant height of the cone.

→ Radius ⇒ Diameter ÷ 2

→ Radius ⇒ 24 ÷ 2

→ Radius ⇒ 12 m

∴ The radius is 12 m.

T.S.A of Cone :-

⇒ $\sf\dfrac{22}{7} \times 12 \times (12 + 21)$

⇒ $\sf\dfrac{22}{7} \times 12 \times 33$

⇒ $\sf\dfrac{22}{7} \times 396$

⇒ $\sf\dfrac{8712}{7}$

⇒ 1244.57 m²

∴ The Total surface area of a cone, if its slant height is 21 m and the diameter of its base is 24 m is 1244.57 m²