## Key Concepts

**Square Root Notation**[latex]\sqrt{m}[/latex] is read ‘the square root of [latex]m[/latex] ’. If [latex]m={n}^{2}[/latex] , then [latex]\sqrt{m}=n[/latex] , for [latex]n\ge 0[/latex] .

**Square Roots and Area**If the area of the square is A square units, the length of a side is [latex]\sqrt{A}[/latex] units.**Square Roots and Gravity**On Earth, if an object is dropped from a height of [latex]h[/latex] feet, the time in seconds it will take to reach the ground is found by evaluating the expression [latex]{\Large\frac{\sqrt{h}}{4}}[/latex].**Square Roots and Accident Investigations**Police officers investigating car accidents measure the length of the skid marks on the pavement. Then they use square roots to determine the speed, in miles per hour, a car was going before applying the brakes. According to some formulas, if the length of the skid marks is [latex]d[/latex] feet, then the speed of the car can be found by evaluating [latex]\sqrt{24d}[/latex].

.**Use a strategy for applications with square roots.**- Identify what you are asked to find.
- Write a phrase that gives the information to find it.
- Translate the phrase to an expression.
- Simplify the expression.
- Write a complete sentence that answers the question.

## Glossary

- Perfect square
- A perfect square is the square of a whole number.

- Square Root of a Number
- A number whose square is [latex]m[/latex] is called a square root of [latex]m[/latex].

If [latex]{n}^{2}=m[/latex], then [latex]n[/latex] is a square root of [latex]m[/latex].