Inclined height of a regular pyramid: Length of the line segment from the vertex, perpendicular to an edge of the base. To find it, what we should do is use the Pythagorean theorem. We have then: d = ROOT ((10/2) ^ 2 + (12) ^ 2) d = ROOT (25 + 144) d = ROOT (169) d = 13 cm Answer: C. 13 cm