Question

review what you have learned before you practise on your own:
converting between units

• the key to converting between units is to use _.
• to check if you have set up your ratios correctly, check the cancelled _.
• when converting between squared units, remember to find the conversion ratio first. for example 1 m² = ( _ )² cm² = _ cm²; therefore, 1 m² = _ cm².

converting rates

• when converting rates, you use _ instead of cross multiplication.
• the key is to _ the units you want to get rid of.
• 1000 m/km can also be written _ km/_ m.
• 60 min/hour can also be written _ hour/_ min.

key terms

• metric system or si
• imperial system
• proportion
• units

Explanation:

Step1: Recall unit - conversion concept

Conversion ratios are used for unit conversion.

Step2: Check ratio - setup

Check the cancelled units to verify ratio setup.

Step3: Square - unit conversion

Since 1 m = 100 cm, 1 m²=(100)² cm² = 10000 cm².

Step4: Rate - conversion

Unit - fraction method is used for rate conversion.

Step5: Cancel units in rate conversion

The key is to cancel the units you want to get rid of.

Step6: Invert conversion factors

1000 m/km can be written as 1/1000 km/m; 60 min/hour can be written as 1/60 hour/min.

Answer:

• The key to converting between units is to use conversion ratios.
• To check if you have set up your ratios correctly, check the cancelled units.
• 1 m²=(100)² cm² = 10000 cm²; 1 m² = 10000 cm².
• When converting rates, you use the unit - fraction method instead of cross multiplication.
• The key is to cancel the units you want to get rid of.
• 1000 m/km can also be written 0.001 km/m.
• 60 min/hour can also be written 1/60 hour/min.