Which of the following is a rational number?

7.8
7.9837377283...
7–√
π

7.8

A rational number is a number that can be expressed as a fraction of two integers.

Out of the options provided, the number 7.8 can be expressed as 78/10, so it is rational.

The number 7.9837377283... is a decimal that continues indefinitely without repeating. Such a number is called an irrational number. Therefore, it is not rational.

The expression 7–√ is not a valid number, since it is missing an operation in between the 7 and the square root. So it cannot be determined if it is rational or not.

Lastly, π (pi) is an irrational number, as it cannot be expressed as a fraction of two integers. So it is not rational.

Therefore, the only number from the options provided that is a rational number is 7.8.