1. Five-Minute Check (over Lesson 1–9) Mathematical Practices Then/Now
New Vocabulary
Example 1: Find Absolute Error
Key Concept: Significant Digits
Example 2: Determine the Number of Significant Digits
Key Concept: Relative Error
Example 3: Real-World Example: Find Relative Error
Lesson Menu

2. Which shows a model of a figure for the orthographic drawing shown?B. D.
5-Minute Check 1

3. What is the left view of the model?C. B. D.
5-Minute Check 2

4. Identify the figure that can be formed from the net; if possible.
A. pentagonal prism
B. pentagonal pyramid
C. hexagonal prism
D. not possible
5-Minute Check 3

5. Which of the following describes the net of a triangular pyramid?
A. 1 triangle, 3 rectangles
B. 1 square, 4 triangles
C. 2 triangles, 3 rectangles
D. 4 triangles
5-Minute Check 4

6. Mathematical Practices 5 Use appropriate tools strategically.
6 Attend to precision. MP

7. You used tools to measure line segments and angles.
Determine precision of measurements.
Determine accuracy of measurements.
Then/Now

8. precision absolute error significant digits relative error accuracy
New Vocabulary

9. Find the absolute error of each measurement. Then explain its meaning.
Find Absolute Error
Find the absolute error of each measurement. Then
explain its meaning.
A. 18 kg
The absolute error of a measurement is equal to one half the unit of measure. A smaller unit of measure provides a more precise measurement.
The absolute error is half of one or 0.5 kg.
This means the exact measurement is 18 ± 0.5 or between 17.5 and 18.5.
Answer: 0.5 kg; the exact measurement is between 17.5 kg and 18.5 kg.
Example 1A

10. Find the absolute error of each measurement. Then explain its meaning.
Find Absolute Error
Find the absolute error of each measurement. Then
explain its meaning. B.
The absolute error of a measurement is equal to one half the unit of measure. A smaller unit of measure provides a more precise measurement.
The absolute error is half of
Example 1B

11. This means the exact measurement is
Find Absolute Error
This means the exact measurement is
or between
Answer: mi; the exact measurement is between
Example 1B

12. Key Concept

13. Determine the number of significant digits in each measurement.
A. 60,070 mi
In whole numbers, zeros are significant if they fall between nonzero digits. Since the last zero comes after the seven it is not a significant digit. This measurement has 4 significant digits.
Answer: 4
Example 2

14. Determine the number of significant digits in each measurement.
B cm
Since this is a decimal number greater than 1, every digit is significant. So, this measurement has five significant digits.
Answer: 5
Example 2

15. Key Concept

16. An advertisement for a circular rug says that the
Find Relative Error
An advertisement for a circular rug says that the
rug has a diameter of 6 feet. Find the relative error
of this measurement.
Answer: about 8.3%
Example 3