Learn imperial units of length including inches, feet, and yards. Math 10-C Alberta curriculum with examples.
Lesson 1.1 of Measurement in Math 10C — Alberta curriculum lessons.
What Is the Imperial System?. In Canada we mostly use the SI (metric) system — centimetres, metres, kilometres. But our biggest trading partner, the United States, uses the imperial system — inches, feet, yards, and miles.
This lesson teaches you the imperial units and how to convert between them.
What Is a Referent?. A referent is an everyday object you use to estimate a measurement without a ruler.
For example: the thickness of a dime is about 1 mm — that dime is your referent for 1 mm.
Where Does "Mile" Come From?. Roman soldiers counted 1 000 paces (one pace = 2 steps) and called that distance a "mile." The Latin word mille means "thousand" — that is literally where the word comes from.
Writing Fractions, Not Decimals. In the imperial system, partial measurements are written as fractions, not decimals.
So you write 312 yd rather than 3.5 yd, or 558 in rather than 5.625 in.
Look at a tape measure — the marks between inches are halves, quarters, eighths, and sixteenths.
What Is Unit Analysis?. The trick to converting units is to multiply by a fraction that equals 1 — like (3 ft)/(1 yd).
Since 1 yd = 3 ft, that fraction equals 1, so multiplying by it does not change the value — it only changes the units.
The Key Setup Rule. Set up the fraction so the unit you want to cancel is on the bottom.
That way the unwanted unit divides out and the new unit is left on top.
Part a) — Convert 6 yd to feet. Conversion fact: 1 yd = 3 ft
Set up: 6 yd × (3 ft)/(1 yd)
Cancel the yards: = 6 × 3 ft
Answer: 6 yd = 18 ft
Part b) — Convert 6 yd to inches. Conversion fact: 1 yd = 36 in
Set up: 6 yd × (36 in)/(1 yd)
Cancel the yards: = 6 × 36 in
Answer: 6 yd = 216 in
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