A drilled conical frustum

Optional extension

A wooden frustum has top radius \(3\) cm, bottom radius \(5\) cm and slant height \(6\) cm. A cylindrical hole of radius \(1.5\) cm is drilled axially through it. Use \(\pi=3.142\).

1. Find frustum height.

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2. The removed wood has mass \(60\) g; find density.

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3. Show the slant height of the small cone originally cut off is \(9\) cm.

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4. Find total surface area after drilling, to \(3\) s.f.

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