Warm Up

1
Warm Up Find the two square roots of each
number. Evaluate each expression.
1. 144 2. 256
12
16
20
119
5. A square window has an area of 169 square
inches, how wide is the window? 6. A square
shaped kitchen table has an area of 16 square
feet. Will it fit through a van door that has a
5 foot wide opening?
2
4-6
Learn to estimate square roots to a given number
of decimal places and solve problems using square
roots.
Course 3
3
Estimating Square Roots of Numbers

• Each square root is between two integers. Name
  the integers. Explain your answer.

4
Example 1
Think What are perfect squares close to 55?
55
49 lt 55
72 49
64 gt 55
82 64
5
Example 2
Think What are perfect squares close to 90?
90

81 lt 90
92 81
100 gt 90
102 100
6
Example 3
Think What are perfect squares close to 80?
80
64 lt 80
82 64
81 gt 80
92 81
7
Example 4
Think What are perfect squares close to 45?
45

36 lt 45
62 36
49 gt 45
72 49
8
Estimating Large Square Roots

• Use a calculator to find answer, round to the
  nearest tenth.

9
Example 5
Use a calculator to find 600. Round to the
nearest tenth.
Using a calculator, 600 24.49489742.
Rounded, 600 is 24.5.
10
Example 6
Use a calculator to find 800. Round to the
nearest tenth.
Rounded, 800 is 28.3.
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Lesson Summary
Each square root is between two integers. Name
the two integers.
1. 27 2. 456
5 and 6
22 and 21
Use a calculator to find each value. Round to the
nearest tenth.
9.4
35.0
3. 89 4. 1223
5. A square field has an area of 2000 square
feet. To the nearest foot, how much fencing would
be needed to enclose the field?
179 ft