The portion of a cone or pyramid which remains after its upper part has been cut off by a plane parallel to its base, or which is intercepted between two such planes.‘An assessment task may ask students to devise a plan for determining the volume of the frustum of a pyramid (a task not previously considered in class).’
- ‘They only appear as frustums because they are being viewed at from an angle.’
- ‘Depending mainly on the thicknesses of the members, the midplane splits one of the two members into two frusta, thus making a total of three frusta to analyse.’
- ‘There are formulas for frustums, but if you think about it, the calculations can be done by extending the frustum height to a vertex and then subtracting the ‘upper’ cone's values from the complete cone yielding the values for the frustum.’
Mid 17th century from Latin, ‘piece cut off’.
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