Find Common Ratio

Free interactive math game: Find Common Ratio — Find q. Part of the Sequences category on MathKite.

Example problems

Taken from the generator that powers this exercise. A fresh set appears every time the page is opened, and the printable worksheet holds ten of them.

  1. Geometric sequence: a₁ = -5, a₄ = 135 Find q = ?
  2. Geometric sequence: a₁ = -2, a₄ = -16 Find q = ?
  3. Geometric sequence: a₁ = -4, a₅ = -64 Find q = ?
  4. Geometric sequence: a₁ = -5, a₄ = -320 Find q = ?

About this exercise

Finding the multiplier of a geometric sequence.

How to solve it

Divide any term by the one before it. The answer is the same everywhere.

Worked example

In 81, 27, 9 the ratio is one third.

Common mistake

Dividing an earlier term by a later one. That gives the reciprocal of the ratio — the sequence run in reverse.