Hi

Let the first term of a G.P is a while  r is the common ratio.
Then,
The First 5 terms of G.P will be given by a,ar, ar^2,ar^3,ar^4
Then,
∴ Third term of the GP=ar^2
Now, we have
Product of first five terms =
a*(ar)*(ar^2)*(ar^3)*(ar^4) = a^5r^10
= (ar^2)^5
= 4^5
= 1024.

Thus , the product of first 5 terms is 1024

Thank you