So, here's what we have got.

The coins are cylindrical, so for the coins....

**r₁=1.5/2=0.75 cm**

thickness is height here, so **h₁****=0.2 cm**

Then for the cylinder..

**r₂=4.5/2=2.25m=225 cm **

**h₂=10 cm**

so, we have got everything in cms, then all that is remained to do is to compare both ones.

so, both are cylinders.

πr₂²h₂=πr₁²h₁*n

Here the 'n' is the no. of the coins.

so, we've got

r₂²h₂=r₁²h₁*n

(225)² (10) = (n) (0.75)² (0.2)

506250=(n) (0.5625) (0.2)

n= 506250*100000/5625*2

so, **n=4,500,000 **

[note: I think there may be a mistake because I'm not sure if the diameter of the main cylinder is 4.5 **meters**, I'd like to tell you to check out if that value is 4.5 **cms**.]

Hope it helped. ^_^