Question

Identify the 19th term of a geometric sequence where a1 = 14 and a9 = 358.80. Round the common ratio and 19th term to the nearest hundredth.

a. a19 ≈ 9,195.53
b. a19 ≈ 31,035.73
c. a19 ≈ 13,185.66
d. a19 ≈ 20,690.

Answer 1

D

Explanation:

Answer 2

The formula of geometric sequence is expressed in the following manner:
an = a1 * r^(n-1) where r is the ratio and n is an integer.
Substituting, to find r
358.80 = 14 * r^(8)
r is equal to 1.5

hence,
a19 = 14* 1.5^(19-1)
a19 ≈ 20,690.