A right pyramid has a square base of side 10 cm and a vertical height of 12 cm. Find the angle between a sloping edge and the base.
- The projection of the edge on the base runs from a corner to the centre: half the diagonal = (10√2) ÷ 2 = 7.071 cm.
- The right-angled triangle has opposite side 12 cm (height) and adjacent side 7.071 cm.
- tan θ = 12 ÷ 7.071 = 1.697, so θ = tan−1(1.697) = 59.5°.
Answer: 59.5° (to 3 significant figures)