5.5 Ratios
• A ratio is a comparison of numbers or quantities ex) brunettes vs. blondes
Blondes=___________
Brunettes=_________
Ratio of Blondes to Brunettes_________
• A ratio of 2 numbers can be written as the following ex) 2 :1, 2 to 1, or as a fraction 2
1
• When writing the ratio, you always have to keep the numbers in the proper order.
• In a part­to­part ratio, you compare one number to another (blondes to brunettes), but in a part­to­whole ratio, you're comparing a number to the total (blondes to everyone)
Feb 2­11:10 AM
3­Term Ratios
• A three term ratio compares three different numbers.
Ex) What is the ratio to people who prefer vanilla ice cream to chocolate to strawberry?
Vanilla_______
Chocolate______
Strawberry_______
• A three term ratio cannot be written like a fraction.
Feb 2­11:16 AM
Turning a Ratio into a decimal or percent
Ex) 1)What is the ratio of circles to squares?
2) What is the ratio of squares to all shapes?
3) What is the ratio of circles to squares to triangles?
A ratio can be written as a fraction. To convert a fraction into a decimal, we divide the top by the bottom, then we convert the decimal, by moving the decimal 2 places to the right, to a percent.
Ex)
5:7 can be written as 5 7
Divide 5 = 0.71
7
Move the decimal 2 places right = 71%
Assignment pg. 266­267 # 5, 6, 8, 9, 11, 14
Feb 2­2:05 PM
Feb 2­2:36 PM
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