Identify the number as a rational or irrational. explai. 291.87

For this case we have to, by definition:

A number is rational when it can be represented as the quotient of two integers. Example:

is a rational number

On the other hand, the irrational numbers are those  that can not be written as quotients of integers. They are characterized because their decimal representation is infinite and non-periodic. Example:

We have: 291.87

This number has a finite decimal expansion. Then it is rational.

Rational