Figure X shows a closed rectangular tank of dimensions 46 cm by 46 cm by 90 cm with a cube of edge 26 cm glued to its bottom right corner. The tank contains 90 litres of water. Figure Y 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 Y 
= 46 - 26
= 20 cm

Volume of water under the cube in Figure Y 
= 90 x 46 x 20
= 82800 cm³ 

1 ℓ = 1000 
90 ℓ = 90000cm³ 

Volume of water beside the cube
= 90000 - 82800
= 7200 cm³ 

Base area of water beside the cube
= (46 x 90) - (26 x 26)
= 4140 - 676
= 3464 cm² 

Height of water level beside the cube
= 7200 ÷ 3464
≈ 2.08 cm

Height of the water level
= 2.08 + 26
≈ 28.08 cm

Answer(s): 28.08 cm