What you need to know

Treat the plinth as a 480 mm wide rounded rectangular block, then subtract the 200 mm x 100 mm pallet slot running through it. Convert cubic millimetres to litres by dividing by 1,000,000.

Tip 1

Start with the full 480 mm x 250 mm x 340 mm block.

Tip 2

Subtract the material removed by the two 50 mm rounded lower corners and the pallet slot.

How to solve it

Full block volume = 480 x 250 x 340 = 40,800,000 cubic mm.

The two rounded corners remove 2 x [50 squared - (pi x 50 squared / 4)] x 480 = 515,044 cubic mm.

Pallet slot volume = 200 x 100 x 480 = 9,600,000 cubic mm.

Concrete volume = 40,800,000 - 515,044 - 9,600,000 = 30,684,956 cubic mm.

Convert to litres: 30,684,956 / 1,000,000 = 30.685 litres.