Right-Angled Trigonometry Involving 3D Example The cuboid below has length AB = 4cm, DE = 6cm and AF = 12cm. Work out the lengths of the diagonals (i) AE (ii) BH (iii) EH D C G H E F B A Example The figure is a pyramid on a square base ABCD. The edges of the base are 30cm long and the height, EH, of the pyramid is 42cm. Find E a) the length of AC b) the angle EAH A D H B C Example ABCDEF is a prism with a triangular crosssection. , BC = 8m, AB = 6m and CD = 20m. E A B F C Find (i) AC (ii) BD D (iii) the total surface area of the prism.