What is the square root of 289?

The square root of 289 is 17. The number 289 is a perfect square, as 17 times 17 is 289. The square of a negative number is a positive number, and this means that -17 times -17 also equals 289. Hence, -17 is also the square root of 289.

A number that is not a perfect square does not have an exact square root. The numbers 100, 121, 144, 169 and 196 are all perfect squares, and their square roots are 10, 11, 12, 13 and 14 respectively. However, numbers such as 20, 30 and 35 are not perfect squares, and their square roots have decimals.