The document focuses on measuring lengths and converting units in the metric system, detailing different devices used for measurement, such as rulers and meter sticks. It provides conversion facts for units related to meter, including kilometers, meters, centimeters, and millimeters, along with examples of how to convert between these units. Additionally, it emphasizes the importance of determining the appropriate unit of length for measurement tasks.

1. Review
• What device is used to measure
time?
• What is 9 years in months?
• What is 4 hours in minutes?
• What is 120 minutes in seconds?
• What is 1 year in days?

2. APRIL 16, 2024, TUESDAY
Lesson 4.2 Measures of Length
Objectives:
• Measure objects according to appropriate
unit of linear measure.
• Convert common units of length from
larger to smaller unit and vice versa.

3. Measures of Length
Reference book pages: 345 - 353

4. Length matters!

5. • Length is how long something is.
• We use different devices to measure
lengths such as the ruler, meter stick and
tape measure.
• Meter(m) is the standard unit of length in
the metric system.
• We use units related to meter for shorter
lengths, namely millimeter (mm),
centimeter (cm), and decimeter (dm).
• We use kilometer(km) for long distances.

6. How will I
know which
unit of length
is appropriate
to use?

8. Estimating Lengths
30 cm
2 m

9. Estimating Lengths
300 cm
55 km

10. Estimating Lengths
10 m
8 cm

11. Estimating Lengths
5 mm
4 m

12. Estimating Lengths
40 cm
5 km

13. Estimating Lengths
6 km
8 m

14. Estimating Lengths
2 cm
20 m

15. Conversion
of units of
length

16. Conversion Facts ( Length)
• 1 km = 1000m
• 1 m = 1 000mm
• 1 m = 100 cm
• 1 m =10 dm
• 1 dm = 10 cm
• 1 cm = 10 mm

17. Convert length measures using
operations
We can change one unit of length
measurement to another.
• Bigger unit to smaller unit,
multiply
• Smaller unit to bigger unit,
divide

18. Example 1
Convert:
6 km to meters
Solution:
6 x 1 000 = 6 000
Answer:
6 km = 6 000 meters
Conversion fact:
1 km = 1000 m

19. Example 2
Convert:
8 m to centimeters
Solution:
8 x 100 = 800
Answer:
8 m = 800 centimeters
Conversion fact:
1 m = 100 cm

20. Example 3
Convert:
3 000 m to kilometer
Solution:
3000 ÷ 1000 = 3
Answer:
3 000 m = 3 kilometers
Conversion fact:
1 km = 1000 m

21. Example 4
Convert:
9 000 mm to meter
Solution:
9000 ÷ 1000 = 9
Answer:
9 000 mm = 9 meters
Conversion fact:
1 m = 1000 mm

22. Textbook Practice
Practice on p. 351
• Practice conversion.
• Write the missing number.