The height of a rectangular pyramid is 30 cm.
volume of rectangular pyramid = (length x width x height) / 3
Given:
Volume = 900 cm³
Length = 10 cm
Width = 9 cm
Height = ?
V = lwh/3
900 cm³ = (10cm * 9cm * h)/3
900 cm³ * 3 = (90cm² * h)/3 * 3
2700 cm³ = 90cm² * h
2700 cm³/90cm² = 90cm² * h/90 cm²
30 cm = h
to check:
900 cm³ = (10 cm * 9 cm * 30 cm)/3
900 cm³ = 2700 cm³/3
900 cm³ = 900 cm³
