holt algebra 1 2-6 rates, ratios, and proportions write and use ratios, rates, and unit rates. write...
TRANSCRIPT
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
Write and use ratios, rates, and unit rates.Write and solve proportions.
Objectives
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
A ratio is a comparison of two quantities by division. The ratio of a to b can be written a:b or , where b ≠ 0.
A statement that two ratios are equivalent, such as , is called a proportion.
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
The ratio of the number of bones in a human’s ears to the number of bones in the skull is 3:11. There are 22 bones in the skull. How many bones are in the ears?
There are 6 bones in the ears.
3
11 22
Ears x
Skull
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
The ratio of games lost to games won for a baseball team is 2:3. The team has won 18 games. How many games did the team lose?
The team lost 12 games.
2
3 18
Lost x
Won
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
A rate is a ratio of two quantities with different
units, such as Rates are usually written as
unit rates. A unit rate is a rate with a second
quantity of 1 unit, such as or 17 mi/gal. You
can convert any rate to a unit rate.
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
Raulf Laue of Germany flipped a pancake 416 times in 120 seconds to set the world record. Find the unit rate. Round your answer to the nearest hundredth.
The unit rate is about 3.47 flips/s.
416 Flips
120 Sec
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
Cory earns $52.50 in 7 hours. Find the unit rate.
The unit rate is $7.50.
$52.50
7 Hours
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
A rate such as in which the two quantities
are equal but use different units, is called a
conversion factor. To convert a rate from one
set of units to another, multiply by a conversion
factor.
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
Serena ran a race at a rate of 10 kilometers per hour. What was her speed in kilometers per minute? Round your answer to the nearest hundredth.
The rate is about 0.17 kilometer per minute.
10 km 1 h 10 km
1h 60 min 60 min
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
60 mi 1 h 5280 ft 5280 ft
1 h 60 min 1 mi 1 min
A cheetah can run at a rate of 60 miles per hour in short bursts. What is this speed in feet per minute?
The speed is 5280 feet per minute.
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
56 mi 1 h 5280 ft 295,680 ft
4 h 3600 sec 1 mi 14,400 sec
A cyclist travels 56 miles in 4 hours. What is the cyclist’s speed in feet per second? Round your answer to the nearest tenth.
The speed is approximately 20.5 feet per second.
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
In the proportion , the products a • d and
b • c are called cross products. You can solve
a proportion for a missing value by using the
Cross Products property.
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
2 48y
2 6 42y
Solve each proportion.
A.B.
3 45m3 3
15m
2 3 42y
6 6
2 224y
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
2 40y
Solve each proportion.
C.
2 220y
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
A contractor has a blueprint for a house drawn to the scale 1 in: 3 ft.
A wall on the blueprint is 6.5 inches long. How long is the actual wall?
The actual length of the wall is 19.5 feet.
in 1 6.5
ft 3 x 19.5x
Holt Algebra 1
2-6 Rates, Ratios, and Proportions
A contractor has a blueprint for a house drawn to the scale 1 in: 3 ft.
One wall of the house will be 12 feet long when it is built. How long is the wall on the blueprint?
The wall on the blueprint is 4 inches long.
in 1
ft 3 12
x 3 12x
HW pp. 117-120/21-49 odd,57-63,66-78 even