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2.6 Ratios and Proportions
A ratio is a ___________ of two quantities.
The ratio of a to b is written: ______ or ___.
Write a ratio for each of the following.
Ratio of 4 dollars to 6 dollars
Ratio of 4 dimes to 3 quarters
A proportion is a statement which expresses
the equality of ____ __________.
Cross – Multiplication
If
a
c
 , then _____ = _____.
b d
a
c

b d
If two ratios are equal, then their cross
products must be equal.
Which of the following proportions are true
statements?
3 7

4 9
15 24

20 32
Find x in the following proportions.
25 x

15
9
Verify.
24
4

x 2 5
Verify.
A university maintains a student-teacher ratio
of 28:3. If a total of 4172 students are
registered for the next spring, how many
teachers will be needed to maintain the ratio?
The distance between Jackson, Mississippi,
and Atlanta, Georgia, is 375 miles. On a certain
map, this is represented by a length of 9
inches. Memphis, Tennessee, and Philadelphia,
Pennsylvania, are situated 1000 miles apart.
Find the length of a line that connects these
two cities on the map.
A taxpayer pays a state tax of $500 on an
income of $15000. If the tax rate remains the
same, how much state tax would he have to pay
if his income increases by $6000?
The length and width of a rectangular lot are
in the ratio 5:3. If the perimeter of the lot is
800 yards, find the length and width.
A certain mixture is made by mixing two
ingredients in the ratio 3:5. If it is required
to make 10 pounds of mixture, how much of
each ingredient will be needed?