Page 61 - Math Course 2 (Book 1)

Squares and Square Roots

MO. 2 - L3b
The negative square root of 319 is between the
whole numbers –17 and –18. Since 319 is closer to
Estimating Square Roots 324 than 289, you can expect that is closer
– 319
to –18 than –17.

Answer –18
Let’s Begin

Real World Example

Estimate Square Roots SKYSCRAPER
The tallest building in Houston, Texas is the
J.P. Morgan Chase Tower, standing at 1,002
Examples foot tall. How far can a person see from the
top f oor on a clear day?

Estimate 22 to the nearest whole number.
A
Use the formula D = 1.22 x where D is
• The f rst perfect square less than 22 is distance in miles and A is the altitude, or height, in
16. = 4 feet.
16
• The f rst perfect square greater than 22 D = 1.22 x A Write the formula.
is 25. = 5
25
= 1.22 x 1002 Replace A with 1002.
• Plot each square on a number line.
= 1.22 x 31.65 Evaluate the square root
16 22 25 f rst.

≈ 38.6 Multiply.
4 5
On a clear day, a person could
The square root of 22 is between the whole num- Answer see about 38.6 miles.
bers 4 and 5. Since 22 is closer to 25 than 16, you
can expect that is closer to 5 than 4.
22

Your Turn!
Answer 5

Estimate Square Roots
Estimate 54 to the nearest whole number.
Estimate – 319 to the nearest whole number.
A. 6
B. 7
• The f rst perfect square less than 319 is 289. C. 8
= 17 D. 9
– 289
• The f rst perfect square greater than 319 is 324. Answer
= 18
– 324

• Plot each square on a number line.
– 324 – 319 – 289

–18 –17

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