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Friday: Quiz
Friday: Grades close
(ALL HOMEWORK IS DUE)
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1
Ex. 3
Suppose you walk 2 miles in 35 minutes. a. Find the average walking speed.
b. Write a rule to describe the distance, d, that you walked as a function of the time, t, you walk. c. Use the function to find how far you would walk in an hour. 2
Converting Rates
To change one unit of measure to another, use rates that equal 1. Rates that equal 1: 1 mile
5280 ft
Ex. 4
Express each rate in miles per hour. a. 1 mile in 6 minutes
Ex. 5
b. 1 mile in 200 seconds A sloth travels 0.15 miles per hour. Convert this speed to feet per minute. Homework: Pg 146 # 7, 8, 38­43 3
Proportions
A ____________________ is an equation that states that two rates are ___________
ex. or Ex. 6 Using the Multiplication Property of Equality
a. x
5
9
6
Property: Cross Products of a Proportion
If a
b ex. 2
3
Proof: If a
b c
d
8
12
c
d
then ad = bc
so 2 12 = 3 8
then ad = bc
4
Ex. 7
Solve the proportion by using cross products
a. 25
12
c. x
4
x + 2 x
14
10
b.
7
y
d. 5 24
3
5
w + 6 w ­ 4
HW: Pg 5
6