Table of Contents
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Table of Contents Topic Pa ... 3.4B Many or No Solution 33 3.8A Solving Equations 35 3.8B Solving Formulas 37 6.5 Absolute Value Equations 39 3.5/3.6 Ratios and Proportions 41
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Table of Contents. Topic Page #. . 3.4B Many or No Solution33. 3.8A Solving Equations35. 3.8B Solving Formulas37. 6.5 Absolute Value Equations39. 3.5/3.6 Ratios and Proportions41. 3.5/3.6 Ratios and Proportions. #41. Ratio:. - PowerPoint PPT Presentation
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Table of ContentsTopic Page #...3.4B Many or No Solution 333.8A Solving Equations 353.8B Solving Formulas 376.5 Absolute Value Equations 393.5/3.6 Ratios and Proportions 41
#41
3.5/3.6 Ratios and Proportions
Ratio:Relation between 2 numbers
a:b ab a to b
You always have to write ratios in the simplest form.
You never write the answer as a mixed fraction
Ex 1: Cell phoneA person makes 6 long distance calls and 15 local calls in 1 month.
a. Find the ratio of long distance calls to local calls.
615
= 25
Ex 1: Cell phoneA person makes 6 long distance calls and 15 local calls in 1 month.
b. Find the ratio of local calls to long distance calls
156
= 52
Ex 1: Cell phoneA person makes 6 long distance calls and 15 local calls in 1 month.
c. Find the ratio of long distance calls to all calls.
621
= 27
Ex 2: SportsA volleyball team plays 14 home matches and 10 away matches.
a. Find the ratio of home matches to away matches.
1410
= 75
Ex 2: SportsA volleyball team plays 14 home matches and 10 away matches.
b. Find the ratio of home matches to all matches.
1424
= 712
Ex 2: SportsA volleyball team plays 14 home matches and 10 away matches.
c. Find the ratio of away matches to all matches.
1024
= 512
Proportions:When two ratios are equal
a cb d
(bd) (bd)
ad = bc
Cross multiplya cb d
ad = bc
Ex #3: Solve.
109 6k
6k = 906 6k = 15
34
x12
4x = 364 4
x = 9
Ex #3: Solve.
34
x12
1 3
x = 9
Reduce around the box
34
x12
4x = 364 4
x = 9
58 24
t
8t = 120
t = 15
58 24
t
1 3
t = 15
y3
31
y = 9
1 33 y
y = 9
863
xx
3(x + 8) = 6x
8 = x
3x + 24 = 6x24 = 3x
3 68x x
x = 8
1 2
2x = x + 8
812
24
xx
24(x – 12) = 8x
18 = x
24x – 288 = 8x–288 = –16x
1224 8x x
x = 18
3 13x – 36 = x2x – 36 = 0
2x = 36
Ex #4: ArchitectAn architect creates a scale model of a school. The school is 50 feet high. The ratio of the model to the actual school is 1 foot to 75 feet. Estimate the height of the model.
modelactual 50
h 1
75
50h
175
2 3
3h = 2
h = 23
Ex #5:A map has a scale factor of 1cm : 15km. If the distance of the map is 6cm, find the actual distance.
115
6x
x = 90
Ex #6:Write the sentence as a proportion and solve.
3 is to 8 as is to 32x
38
32x
1 4
x = 12
Ex #6:Write the sentence as a proportion and solve.
x is to 4 as 8 is to 16
4x
8161 4
x = 21
2
