Target Mathematics

1.97: 3D angles in a pyramid

4PM1/2/June/2015 — Question 7 · 12 marks

1.97 diagram 1
Figure 2 shows a solid VABCDEFGHVABCDEFGH which is formed by joining a cuboid ABCDEFGHABCDEFGH to a right pyramid VABCDVABCD. The height of the cuboid and the height of the pyramid are both hh cm and FG=8FG=8 cm and GH=6GH=6 cm. The total volume of the solid is 256 cm3256\text{ cm}^3.
(a) Show that h=4h=4. (2)
(b) Find, in cm to 3 significant figures, the length of VFVF. (3)
Find, to the nearest 0.10.1^\circ,
(c) the angle between VAVA and the plane ABCDABCD, (3)
(d) the acute angle between the plane VABVAB and the plane ABHEABHE. (4)