Answer: the fourth term is 11.5
Explanation:
Looking at the graph of a(n) on the y(vertical) axis and n on the x(horizontal) axis, the slope is expressed as
(y2-y1)/(x2-x1) = (4 - 10)/(5 - 1) = -6/4
Slope = -1.5
This means that in the arithmetic sequence, each successive term differs by - 1.5.
The first term of the sequence is 10. It started decreasing.
The formula for the nth term of an arithmetic sequence is expressed as
Tn = a + (n - 1)d
Where
a is the first term
n is the number of terms
d is the common difference
From the information given,
a = 10
d = -1.5
n = 4( we want to determine the value of the term). Therefore
T4 = 10 + (4-1)× -1.5
T4 = 10 + (3×-1.5)
T4 = 10 - 4.5 = 11.5