Ratios
•
•
A ratio is a comparison of two numbers.
Can be written in several ways:
0011 0010 1010 1101 0001 0100 1 011
Solving Equations Pt. II
Proportions
1
0011 0010 1010 1101 0001 0100 1011
Wednesday
9/9/09
2
45
Proportions
•
A proportion is an equation with two ratios
(written
fractions)
0011 0010
1010 1101as
0001
0100 1 011 set equal to each other.
12 9
=
x 5
•
•
y − 4 − 12
=
11
5
1
2
Proportions are used often in math and science.
All proportions can be solved the same way.
45
Distributive Property
You may have to use the distributive property when you
cross
0011 0010
1010multiply.
1101 0001 0100 1 011
y − 4 − 12
=
5 5(y – 4)
-12(11) 11
-132 = 5y – 20
–
–
–
•
30:7 (used in finding odds, mixtures, etc.)
13 to 4
4/7
1
2
Ratios are used in math, science, auto,
agriculture, cooking and many other areas.
45
Steps for Solving Proportions
1. Cross Multiply –
0011 0010
1010 1101 the
0001 top
0100 1
Multiply
of011
one ratio by the
bottom of the other
ratio. This will get
rid of the fractions.
2. Solve the remaining
equation
12 9
=
9(x) x 5 12(5)
9x = 60
9
9
1
x = 6⅔
2
45
Assignment
0011 0010 1010 1101 0001 0100 1 011
Solving Proportions Problems
1
2
45
1
2
45
1