Question

A

Which of the following is
an irrational number?
√21
B
√64
C
15
22

Answer 1

Answer: a. √21.

Step-by-step explanation:To determine which of the following options is an irrational number, we need to understand what an irrational number is. An irrational number is a number that cannot be expressed as a fraction or a ratio of two integers.

Now let's evaluate each option:

a. √21: This is an irrational number because the square root of 21 cannot be expressed as a simple fraction or ratio of two integers.

b. √64: This is a rational number because the square root of 64 is 8, which can be expressed as the ratio of two integers (8/1).

c. 15: This is a rational number because it can be expressed as the ratio of two integers (15/1).

d. 22: This is a rational number because it can be expressed as the ratio of two integers (22/1).