Question

which of the following is/are rational number(s)? 21, the square root of 5, 4/5, pi

Answer 1

only 4/5

the others are non-repeating non-terminating decimals, so irrational

Answer 2

oops - I missed the 21, which is an integer, hence rational, with a denominator of 1.

Answer 3

[AI-generated answer — Explain Bot]

To identify the rational number(s) among the options given, we need to understand what rational numbers are.

Rational numbers are numbers that can be expressed as a fraction (ratio) of two integers, where the denominator is not zero. In other words, rational numbers can be written in the form of p/q, where p and q are integers and q is not equal to zero.

Now, let's analyze the options given:

1. 21: 21 can be written as 21/1, where 21 and 1 are integers. Therefore, 21 is a rational number.

2. The square root of 5: The square root of 5 (√5) is an irrational number. Irrational numbers cannot be expressed as a simple fraction, and their decimal representations never terminate or repeat. Therefore, √5 is not a rational number.

3. 4/5: 4/5 is a fraction where the numerator (4) and denominator (5) are both integers. Thus, 4/5 is a rational number.

4. π (pi): Pi (π) is an irrational number. It is a mathematical constant representing the ratio of a circle's circumference to its diameter. The decimal representation of pi goes on indefinitely without a pattern, and it cannot be expressed as a fraction of two integers. Therefore, pi is not a rational number.

In summary, the rational numbers among the options provided are 21 (21/1) and 4/5.