# Pre-Algebra Comparing and Scaling 2.3

```Pre-Algebra
Comparing and Scaling 2.3
Monday, September 8
Problem 2.2 ACE Questions #1 and #2
What did we do last time 2.2
In investigation 2.2 we completed a table to
pizza prices for Howdy and Royal Pizza
What was the equation we came up with for
Howdy’s pizza?
Equation for Howdy’s Pizza: P=13n
Equation for Royal Pizza: P=12n
What does the 13 represent in the equation for Howdy’s pizza?
What does the 12 represent in the equation for Royal’s pizza?
Learning Target
I will be able to identify a unit rate in
• a description,
• an equation
• a table, or
• a graph.
Vocabulary
Constant of proportionality: The constant ratio
of two proportional quantities, x and y; usually
written as y = kx, where k is the constant of
proportionality. For example in the equation
y= ¾ x, the constant or proportionality is ¾. The
graph for this relationship is shown below.
Who can tell me the definition of
a unit rate?
Problem 2.3 A
Problem 2.3 A
Number of
oranges (n)
10
5
1
20
11
13
Cost, C
\$2
\$1
\$.20
\$4
\$2.20
\$2.60
Problem 2.3 A
Number of
oranges (n)
10
5
1
20
11
13
Cost, C
\$2
\$1
\$.20
\$4
\$2.20
\$2.60
Problem 2.3 A
5a. Every time the cost of oranges goes up by \$1, the number of oranges increases by 5.
5b. C = .20n, this equation says that every time the number of oranges goes up by 1, the
cost goes up by \$.20.
5c. \$.20/1 orange
and
5 oranges/\$1
5d. The constant of proportionality and the unit rate are the same.
Number of
oranges (n)
10
5
1
20
11
13
Cost, C
\$2
\$1
\$.20
\$4
\$2.20
\$2.60
Problem 2.3 B
Problem 2.3 B
Problem 2.3 B
Problem 2.3 C
Problem 2.3 C
Problem 2.3 C
4. Gus should buy the pasta at Fresh Foods, it is \$.83/box.
I will be able to identify a unit rate in
• a description,
• an equation
• a table, or
• a graph.
Homework
ACE Questions P. 51 #9 and #10
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