Transcript Section 2.6

Section 2.6
RATIOS, RATES, AND
CONVERSIONS
Ratio
 Compares two numbers by division
 Can be written in 3 ways:
a
a:b
a to b
b
Must always be simplified!!
 Meaning – for every a units of one quantity, you have b
units of another quantity
 Example: the number of boys to girls in class is 2 to 1
Rate
 A ratio that compares quantities measured in
different units
 A rate with a denominator of 1 unit is called a
unit rate
Comparing Unit Rates
 Write each ratio as a unit rate THEN compare
 Example:
 You are shopping for T-shirts. Which store offers the better
deal?
Store A: $25 for 2 shirts
 Store B: $45 for 4 shirts
 Store C: $30 for 3 shirts

Converting Units
 To convert from one unit to another, such as feet to
inches, you multiply the original unit by a conversion
factor that produces the desired unit.
 Conversion
factor – a ratio of two equivalent measures in
different units
 Conversion factors ALWAYS equal to 1
 ALWAYS
place the given conversion on the bottom on
the conversion factor
 Example:
1 ft
12 in
**** PAGE 723 has Conversions
Example
 Convert the given amount to the given unit
 330 min; hours

● 15 kg; grams
330 min · 1 h
60 min
● 5 ft 3in; inches
Converting Rates with 2 Different Units
 You must multiply by two conversion factors in order
to change both of the units.
 Example:
 A student ran the 50-yard dash in 5.8 seconds. At what speed
did the student run in miles per hour? Round your answer to
the nearest tenth.
50 yards
5.8 sec