# What is the next number in this geometric sequence -3.24, 9.72, -29.16, 87.48?

Nov 8, 2015

The next term is $- 262.44$

#### Explanation:

We can write an expression as follows for the nth term. The signs alternate between negative and positive. Each term is 3 times more that the preceding one with a different sign.

$\left(- 3.24\right) {\left(- 3\right)}^{n}$ where $n$ is an integer starting at $0$

$\left(- 3.24\right) {\left(- 3\right)}^{0} = - 3.24$

$\left(- 3.24\right) {\left(- 3\right)}^{1} = 9.27$

$\left(- 3.24\right) {\left(- 3\right)}^{2} = - 29.16$

$\left(- 3.24\right) {\left(- 3\right)}^{3} = 87.48$

$\left(- 3.24\right) {\left(- 3\right)}^{4} = - 262.44$