Answer: 1620
Step-by-step explanation:
To solve the question, we would.use a geometric progression to solve the question. This is given as;
= ar^n-1
where
a = first term = 60
r = ratio = 180/60 = 3
4th term = ar^n-1 = ar^4-1 = ar^3
= 60 × 3^3
= 60 × 27
= 1620