Transcript 1.4 Estimating Square Roots

Chapter 1: Square Roots and
the Pythagorean Theorem
Estimating Square Roots
Reminder:
Perfect squares are the set of numbers:
1, 4, 9, 16, 25, 36, 49…
 They are formed by squaring the natural
numbers (or whole numbers): 1, 2, 3, 4, 5 …
 Numbers such as 2, 3, 5, and 6 are not
perfect squares because they do not have
whole number square roots.

What we know already…
You know that a square root of a
given number is a number which,
when multiplied by itself, results in
the given number.
 For example: √9 = √3 x 3 = √32 = 3
 You also know that the square root of
a number is the side length of a
square with area that is equal to that
number.
 For example: √9 = 3

Use a copy of the number line given to
you.
 Place each square root on the number line
to show its approximate value:
√2, √5, √11, √18, √24
 Write each estimated square root as a
decimal.

Quick Review of Decimals:
What strategies did you use to estimate
square roots?
 How could you use a calculator to check
your estimates?



I could multiply the decimal number by itself,
then check how close the product is to the
given number.
Look at example 2 on page 24.
Homework
P. 25 #4, 5, 7, 8, 9, 12, 13 (you’ll need a
calculator for 12 and 13)
 Use the number lines given to you to
complete #8
 Due: Monday, Sept. 27
