The Surface area of the whole cone is 4408.56 cm²
The Surface area of the tips that is removed is 376.8 cm²
The Surface area of the megaphone(hollow) is 2712.96 cm²
What is surface area?
Surface area is the sum of the areas of all faces (or surfaces) on a 3D shape.
Therefore,
Surface area of the whole cone = πr² + πrl
Therefore,
Surface area of the whole cone = πr(r + l)
where
- r = radius = 18 cm
- l = edge length = 60 cm
Surface area of the whole cone = 3.14 × 18(18 + 60) = 4408.56 cm²
Surface area of the tips that is removed = 3.14 × 4 (18 + 12) = 376.8 cm²
Surface area of the megaphone(hollow) = πrl
Surface area of the megaphone(hollow) = 3.14 × 18 × (60 - 12) = 2712.96 cm²
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