please can you give a short explanation as well thanks

Answer:
Step-by-step explanation:
Volume of the cylindrical tank = πr²h
= 3.14 * 100 * 100 * 250
= 7850000 cm³
Volume of half tank = 7850000 ÷ 2
= 3925000 cm³
1000 cm³ = 1 litre
3925000 = 3925000 ÷ 1000
= 3925 litre
= 4000 litre