The diameter of a right circular cone is 42 cm and its height is 20 cm. Calculate the total surface area of the cone.
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Correct answer: D
Explanation
Diameter = 42 cm ⇒ Radius = 21 cm
Height = 20 cm
l = √(r² + h²)
TSA = πr(l + r)
l = √(21² + 20²) = √841 = 29
TSA = π × 21 × (29 + 21) = 3300 cm²