Practice Geometric Sequence in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

A sequence where each term is obtained from the previous by multiplying by a fixed non-zero constant called the common ratio r.

Multiply by the same number each step โ€” 2, 6, 18, 54, ... (multiply by 3). This is exponential growth.

Example 1

easy
A geometric sequence has a_1 = 5 and r = 2. Find a_8 and S_8.

Example 2

medium
Bacteria double every 3 hours. Starting with 500, how many after 15 hours?

Example 3

easy
Find r and a_6 for the sequence 3, 6, 12, 24, \ldots

Example 4

hard
In a geometric sequence, a_2 = 6 and a_5 = 48. Find a_1 and r.

Example 5

medium
Find the 6th term of the geometric sequence: 2, 6, 18, ...