Question

a cone has a radius of 6cm and height 9 calculate a)the volume and curved surface area b) total surface area

Answer 1

Answer:

V = 339.3 cm³; L = 203.9 cm²; A = 317.0 cm²  

Step-by-step explanation:

a) Volume

The formula for the volume (V) of a cone is

V = ⅓πr²h

V = ⅓π × 6² × 9

V = ⅓π × 36 × 9

V = 108π cm³

V ≈ 339.3 cm³

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Curved surface area  

The formula for the lateral surface area (L) of a cone is

L = πr√(r² + h²)

L = π×6√(36 + 81)

L = 6π√[9(4 + 9)]

L = 6π√(9 × 13)

L = 18π√13 cm²

L ≈ 203.9 cm²

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b) Base surface area

The base is a circle, so the formula for base surface area (B) is

B = πr²

B = π×6²

B = 36π cm²

B ≈ 113.1 cm²

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Total surface area

A = L + B

A = 18π√(13 +36π)

A = 18π(2 + √13) cm²

A ≈ 203.9 + 113.1

A ≈ 317.0 cm²