1. 7.1 Ratio and Proportion Objectives: I will be able to…
Discover and simplify ratios
Discover and solve proportions
Solve real life problems using ratios & proportions

2. Intro Who likes Coca-Cola?
Ever wonder how much sugar you are really putting into your body each time you drink one?

3. Vocabulary or a to b or a : b Ratio: comparison of two quantities.
Ratio of a and b (3 ways to write it):
or a to b or a : b
Because a ratio is a quotient,
the denominator cannot be zero

4. Using Ratios
Find the ratio of the length to width if AB = 36 cm and BC = 24 cm. A B D C
*Always simplify

5. Using Ratios
The perimeter of an isosceles triangle shown is 56 inches. The ratio of LM : MN is 5 : 4. Find the lengths of the sides and the base of the triangle. L
20in:20in:16in M N

6. Using Ratios
The perimeter of a triangle is 45in and the ratio of side is 1:3:5. Find the length of each side.
5, 15, 25 in
In a triangle, angles are in the ratio of 3:4:8. Find each angle.
36°, 48°, 96°

7. Using Ratios in Real Life
The ratio of male students to female students in the drama club at Campbell High School is 3:4. If there are a total of 42 students in the club, how many male and female students are there?
18 males and 24 females

8. Vocabulary Proportion – two equal ratios made up of means and extremes

9. Are the following equations proportions?b) c)
Simplify each ratio!

10. Vocabulary
Cross Product Property– the product of the extremes equals the product of the means.
Means
ad = bc
Extremes

11. Solving proportions. a)
X = 6 b)
y = ½ c)
z = -8

12. Using Proportions in Real Life
A construction worker is placing rivets in a new bridge. He uses 42 rivets to build the first 2 feet of the bridge. If the bridge is to be 2200 feet in length, predict the number of rivets that will be needed for the entire bridge.
46, 200 rivets!

13. Exit Ticket
So, how many sugar packets do you think are in a 20-oz. bottle of Coca-Cola?
Based on the fact that there are 4 grams of sugar in 1 sugar packet, how many sugar packets are actually in a 20-oz. bottle of Coca-Cola?

14. Geometry
Homework:
p. 464 #12-14, 30, 40, 44, 46