JAMB - Mathematics (1982 - No. 34)
The square base of a pyramid of side 3cm has height 8cm. If the pyramid is cut into two parts by a plane parallel to the base midway between the base and the vertex, the volumes of the two sections are
(21cm3, 3cm3)
(24cm3, 3cm3)
(24cm3, 21cm3)
(72cm3, 9cm3)
(63cm3, 9cm3)
คำอธิบาย
Vol. of the 1st section is side x height
vol. = 3 x 8
= 24cm3
vol. of the second section is 3 x 1 = 3
= 24cm3, 3cm3
vol. = 3 x 8
= 24cm3
vol. of the second section is 3 x 1 = 3
= 24cm3, 3cm3