Question

Find the total surface area of a lone , if its stand height is 9m and the radius is of its lease is 12 m.​

Answer 1

Step-by-step explanation:

Total surface area of a cone =πr(r+l)

Hence, TSA of this cone, = 22/7 × 12 × (12+9)

= 792m²

Answer 2

Correct Question :-

Find the total surface area of a cone whose slant height is 9 m and the radius of its base is 12 m.

Step-by-step explanation:

Given :-

• Slant height of the cone = 9 m
• Radius of the cone = 12 m

To find :-

• Total surface area of cone.

Solution :-

• Slant height = 9 m
• Radius =12 m

Formula used :

${\boxed{\sf{TSA\:of\: cone=\pi\:r(r+l)}}}$

Total surface area of cone,

= πr(r+l)

= [(22/7) × 12 (12+9)] m²

= [(22/7) × 12 × 21] m²

= 5544/7 m²

= 792 m²

Therefore, the total surface area of the cone is 792 m².

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Additional info :-

• Volume of cylinder = πr²h
• T.S.A of cylinder = 2πrh + 2πr²
• Volume of cone = ⅓ πr²h
• C.S.A of cone = πrl
• T.S.A of cone = πr(r+l)
• Volume of cuboid = l × b × h
• C.S.A of cuboid = 2(l + b)h
• T.S.A of cuboid = 2(lb + bh + lh)
• C.S.A of cube = 4a²
• T.S.A of cube = 6a²
• Volume of cube = a³