### Home > A2C > Chapter 3 > Lesson 3.2.3 > Problem3-125

3-125.

Decide whether each sequence below is arithmetic, geometric, or neither. Then find equations to represent each sequence, if possible.

1. $10.3, 11.5, 12.7, …$

Notice that the increase is not a constant number.

The sequence is arithmetic.
$t\left(n\right) = 9.1 + 1.2n$

1. $\frac { 1 } { 2 }$, $\frac { 1 } { 4 }$, $\frac { 1 } { 8 }$, …

Notice the ratio.

1. $1, 4, 9, …$

Notice that each number is a perfect square.

1. $1.1, 1.21, 1.331, …$

Notice that the sequence's increase is constant.

Remember what $11$ squared is.

The sequence is geometric.
$t\left(n\right) = 1.1^{n}$