Answer:
1.25
Step-by-step explanation:
a = 10 and r = 0.5
The formula for calculating any term in a geometric sequence is a (the first term) times r (the common ratio) raised to the power of n - 1.
In this case n = 4, since we're looking for the fourth term.
so,
Un = ar^n-1
= ar^4-1
= ar^3
U4 = 10 × 0.5^3
= 10 × 0.125
= 1.25
