(b)  53 litres = 53000ml = 53000 cm³

Area of trapezium = (1/2)(sum of parallel sides)h

Therefore, Volume of water  =  Area of trapezium x depth

(1/2)(10+32)h x 62 = 53000

(42/2)h x 62 = 53000

h = 53000/1302  =  40.7cm ( 1 decimal place)