225k views
2 votes
Find the missing term in this geometric sequence:


2,(?),98

1 Answer

4 votes

Answer:

The missing term is 14

Explanation:

The sequence is a geometric sequence .The first term is 2 and the third term is 98 .The question wants us to find the second term .

Since we know the 3rd term the common ratio can be solved using the nth term equation for geometric sequence

nth term = arⁿ⁻¹

where

r = common ratio

n = number of terms

nth term = arⁿ⁻¹

98 = 2r³⁻¹

98 = 2r²

divide both sides by 2

r² = 98/2

r² = 49

square root both sides

r = √49

r = 7

The common ratio is known let us find the second term which is the missing term.

nth term = arⁿ⁻¹

arⁿ⁻¹

2 × 7²⁻¹

2 × 7 = 14

The missing term is 14

User Steve Potter
by
4.8k points