LESSON 4: ESTIMATING SQUARE ROOTS

Learning Outcome: Learn to develop strategies for estimating a square root.

LESSON 4: ESTIMATING SQUARE ROOTS

The square root of a number when multiplied by itself, results in the given number.Ex.

This also gives us the side length of a square.

Recall:

16 squares = 4 x 4 or

Place each square root on the number line to show its approximate value:

A perfect square root is a number when we square root it results in a whole number.

One way to estimate the square root of a number is to compare your number to numbers that you already know the square roots of.

Ex. What is the square root of 30?

First find the perfect square roots that are close to 30.30 is in between the perfect squares of 25 and 36 so the square root of 30 should be between 5 and 6.

Since 30 is closer to 25 than 36, the decimal should be less than half way between 5 and 6, therefore 5.4 would be a good estimate.

You can check by using your calculator.

Ex. Estimate and diagram

The number will fall between the perfect squares 16 and 25.

Assignment: pg. 25-27 #1-16, 19-21

You can also write the quiz for Lesson 3 when you are ready Practice