Unit 2A

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Unit 2A

• The Problem-Solving Power of Units

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UNITS
The units of a quantity described what is being
measured or counted.
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READING UNITS
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UNIT CONVERSIONS
To convert from one unit (say old ) to
another unit (say new ), we multiply by a
conversion factor in an equivalent form of 1,
whose denominator has old units and whose
numerator has new units. The old units
will cancel.
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EXAMPLES OF UNIT CONVERSION
1. 7 days 1 week has unit conversions.
(a) Convert 28 days to weeks. (b) Convert 28
weeks to days.
2. How many inches are in 9 feet? 3. Convert
160 oz to lb.
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4. A vacant lot has an area of ¾ acre. What is
its size in square feet? (1 acre 43,560
ft2) 5. A car is driving at 75 miles per hour.
What is its speed in miles per minute?
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USING A CHAING OF CONVERSIONS
2. How many seconds are there in 2
days? 3. Convert 15 miles to yards. 4. Convert 3
weeks into seconds.
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CONVERSION WITH UNITS RAISED TO A POWER
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1. Convert 6 ft2 to in2. 2. Convert 2000 in2 to
ft2. 3. Convert 99 ft2 to square yd. 4. Convert
108 yd2 to square ft. 5. How many cubic yards of
soil are needed to fill a planter that is 20 feet
long by 3 feet wide by 4 feet tall?