Figure R shows a closed rectangular tank of dimensions 44 cm by 44 cm by 85 cm with a cube of edge 25 cm glued to its bottom right corner. The tank contains 90 litres of water. Figure S shows the same rectangular tank lying on its side. Find the height of the water level, in centimetres, corrected to 2 decimal places.
Height of water under the cube in Figure S 
= 44 - 25
= 19 cm

Volume of water under the cube in Figure S 
= 85 x 44 x 19
= 71060 cm³ 

1 ℓ = 1000 
90 ℓ = 90000cm³ 

Volume of water beside the cube
= 90000 - 71060
= 18940 cm³ 

Base area of water beside the cube
= (44 x 85) - (25 x 25)
= 3740 - 625
= 3115 cm² 

Height of water level beside the cube
= 18940 ÷ 3115
≈ 6.08 cm

Height of the water level
= 6.08 + 25
≈ 31.08 cm

Answer(s): 31.08 cm