1. Find the unit rate for 55 cakes / 5 miles.
Bellringer
82 cookies / 30 cupcakes
9 hotdogs / 1 hour
Which is a rate?
Which is a unit rate?
Find the unit rate for 55 cakes / 5 miles.

2. Go over Homework
Reteach 5-2
Reteach 5-3

3. Ch. 5-3 & 5-4 Proportions & Solving Proportions

4. cross products Aka: cross Multiply
two products found by multiplying the denominator of each ratio by the numerator of the other ratio
20 = 6
90 = 90
6 = 9

5. proportion
an equation stating that two ratios are equal – use cross products to determine if a proportion or not
No, not a proportion
20 = 6
90 = 90
6 = 9
No, not a proportion
Yes a proportion

6. Example 1: Determine whether the following ratios form a proportion.
a.) b.)
Yes, because cross products are equal 60 = 60
No, because cross products are not equal 10 = 8

7. Example 2: Solve each proportion below by using the cross products.
a.) b.)
c.) d.)
Times the couple together 9 & 10
Then divide by the lonely guy 2
X = 45
Times the couple together 4 & 21
Then divide by the lonely guy 12
x = 7
Times the couple together 20 & 9
Then divide by the lonely guy 15
x = 12
Times the couple together 12 & 6
Then divide by the lonely guy 8
x = 9

8. Example 3: Set up a proportion for each scenario below and solve by doing the cross products.
a.) Andy paid $1.29 for 3 pieces of candy. At that rate, what would 8 pieces of candy cost?
b.) You are visiting friends in Estonia. Suppose the exchange rate is kroons = 1 dollar. How many Estonia kroons will you receive if you have $500?
Times the couple together 1.29 & 8
Then divide by the lonely guy 3
x = $3.44
Times the couple together & 500
Then divide by the lonely guy 1
x = 6,340 kroons

9. Which triangles are similar? 8 20 12 4 10 8
Which triangles are similar?
If they are in proportion they are similar.

10. Blue and Red are similar (they are in proportion)8 20 12 4 10 8
20 x 4 ?? 8 x 10
8 x 8 ?? 12 x 4
12 x 10 ?? 20 x 8
Equal => Yes
Equal => NO
Equal => NO
Blue and Red are similar
(they are in proportion)

11. Homework
PS 5-4 all

12. Pg. 240 #10-26 even (1 pt each) Pg. 247 #12-24 even (1 pt each)
Homework
Pg. 240 #10-26 even (1 pt each)
Pg. 247 #12-24 even (1 pt each)

13. Bellringer Which triangles are similar?8 20 12 4 10 8
Which triangles are similar?
If they are in proportion they are similar.

14. Go over Homework
Pg. 240 #10-26 even
Pg. 247 #12-24 even

15. Proportion Project Head and Shoulders Practice Sheets 5-3 & 5-4
Do in class
If not completed homework