Page 501 - Canadian BC Science 9

The mass of the table salt and beaker together is 230 g. Therefore, the mass of the salt is 70 g.
Instant Practice—Measuring Mass
Determine the masses represented on the following centigram balances.
Measuring Angles
You can use a protractor to measure angles. Protractors usually have an inner scale and an outer scale. The scale you use depends on how you place the protractor on an angle (symbol 􏰀􏰈). Look at the following examples to learn how to use a protractor.
Example 1
What is the measure of 􏰈XYZ?
Solution
Place the centre of the protractor on point Y. YX crosses 0° on the outer scale. YZ crosses 70° on the outer scale. So 􏰈XYZ is equal to 70°.
Z
YX
Example 2
Draw 􏰈ABC 􏰀 155°.
Solution
First, draw a straight line, AB. Place the centre of the protractor on B and line up AB with 0° on the inner scale. Mark C at 155° on the inner scale. Join BC. The angle you have drawn, 􏰈ABC, is equal to 155°.
A 0
0 10 20 30 40 50 60 70 80 90 100g
B
C
0 10 20 30 40 50 60 70 80 90 100g
0
0
0
0.4
0.5 0.6 0.7 0.8
100
0.9 0.10g
200g
0 1 2 0.1 0.2
0
3 0.3
4 5 6 7 8 9 10g
100 200g
0 1 2 0.1 0.2
0
3 0.3
4 5 6 7 8 9 10g
0.4
0.5 0.6 0.7 0.8
100
0.9 0.10g
200g
0 10 20 30 40 50 60 70 80 90 100g
0 1 2 3 4 5 6 7 8 9 10g
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.10g
Science Skill 7 • MHR 483