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Technology
Activity
CALCULATOR
Using Square Roots and Pi
GOAL Use a calculator to evaluate expressions involving square roots and π.
You can use the keystrokes
Example 1
[ 1 ] and the
key to evaluate expressions.
A square field has an area of 4840 square yards, or 1 acre.
Between what two whole-number lengths does the length
of a side of the field fall? Use a calculator to check your
answer.
Solution
with
Technology
Most calculators will display
an error message if the
square root of a negative
number is evaluated.
Because 4840 falls between the perfect squares 4761 692 and 4900 702,
falls between 69 and 70.
you know that 4840
.
Check your answer by evaluating 4840
Keystrokes
Display
69.57010852
[ 1
] 4840
ANSWER The length falls between 69 yards and 70 yards.
Example 2
Evaluate 16π. Round to the nearest hundredth.
Solution
Keystrokes
Display
50.26548246
16
ANSWER 16π ≈ 50.27
Your turn now
Approximate the square root to the nearest
hundredth. Then use a calculator to check your answer.
1. 467
2. 1056
3. 4356
4. 3
7
,8
8
8
Use a calculator to evaluate the expression. Round to the
nearest hundredth.
5. 41π
6. 36π
7. π3
Lesson 11.7
8. 14π2
Area of a Circle
571