You may also like

problem icon

In a Spin

What is the volume of the solid formed by rotating this right angled triangle about the hypotenuse?

problem icon

Conical Bottle

A right circular cone is filled with liquid to a depth of half its vertical height. The cone is inverted. How high up the vertical height of the cone will the liquid rise?

problem icon

Peeling the Apple or the Cone That Lost Its Head

How much peel does an apple have?


Age 14 to 16 Challenge Level:

A plastic funnel is used to pour liquids through narrow apertures.

Have you ever tried pouring a drink from a glass back into a bottle ?

If we imagine a funnel as a complete cone (why isn't it?), what shape cone would use the least amount of plastic to manufacture a funnel containing a set volume?

You don't need a specified volume, but it may help to ask what proportion cone would hold a litre of liquid using the least amount of plastic.

See the Hint for more help.