Square Root Definition: a plain-English explanation of what the term means, why it matters in math, and how it is used, followed by worked examples and practice questions so the definition turns into something you can apply.
Math Dictionary / Square Root
Square Root
A square root of a number is a value that multiplies by itself to make that number.
Number SystemGrade 8Algebra 1GEDSATACT
What it means
The square root of 36 is 6 because 6 x 6 = 36.
Also called: radical
Examples
| sqrt(25) = 5 |
| sqrt(81) = 9 |
| sqrt(2) is about 1.414 |
Common mistake
The principal square root is non-negative. sqrt(49) means 7, not -7.
Try one
Question: What is sqrt(144)?
Show answer
12, because 12 x 12 = 144.