Sentence:  Problem 22. Determine the volume of a <WSD>frustum</WSD> of a sphere of diameter 49.74 cm if the diametersic of the ends of the <WSD>frustum</WSD> are 24.0 and 40.0 cm, and the height of the <WSD>frustum</WSD> is 7.00 cm. 
Meaning of the word marked with <WSD> tags:  A portion of a sphere, or in general any solid, delimited by two parallel planes.