Find the number of coins, 1.5 cm in diameter and 0.2 cm thick, to be melted to form a right circular cylinder with a height of 10 cm and a diameter of 4.5 cm.
Volume of coin = 
r2h = 
Volume of cylinder = 
r2h = 
Therefore,
Total number of coins = 
= 
= 450 coins
Thus, 450 coins must be melted to form the required cylinder
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