How to calculate volume of trapezoidal footing?

Trapezoidal Footing = Cuboid + Truncated Pyramid

Rectangle Cuboid = Length x Breadth x Height

Truncated Pyramid =

Where,

A1 = Area of Top Base

A2 = Area of Bottom Base

H = Height

A1 = 600 x 400

A1 = 0.24 m²

A2 = 3 x 2

A2 = 6 m²

Example:

Volume of Cuboid

= (L x B x H)

= (3 x 2 x 200 mm)

= 1.2 m³

Volume of Truncated Pyramid

= [ 1/3 (0.24 + 6 + 6.004  ) x 0.4]

= 1.632 m³

Volume of Trapezoidal Footing = Cuboid + Truncated Pyramid

= 1.2 + 1.632

= 2.832 m³