Warm Up1. A concession stand at a baseball game

sells 3 apples for $2.00. How can you find the cost for 10 apples?

2. Solve for x: 3(x + 5) = 2x – 10 + 4x

3. What is the solution of the proportion

4. A 10-ft tall flagpole stands next to a tree. The shadow of the flagpole is 17 ft and the shadow of the tree is 50 ft. What is the height of the tree?

5

4

2

1

xx

Homework Questions?

Let’s go over problems…

Applications of Proportions!

SWBAT find missing side lengths of triangles by setting up and solving a proportion.

SWBAT convert between different units by setting up and solving a proportion.

SWBAT find the missing percents and amounts by setting up and solving a proportion.

Proportions in Geometry

You try.

Comparing Unit Rates

Think about this and discuss with your neighbor… You are shopping for T-shirts. Which

store offers the best deal? Why? Store A: $25 for 2 shirts Store B: $45 for 4 shirts Store C: $30 for 3 shirts

Using Proportions to Convert Units

To convert from one unit to another, such as feet to inches, multiply by a conversion factor to produce the desired units.

A conversion factoris a ratio of 2 equivalent measures in different units.

In other words, we set up a proportion with two equivalent ratios to find our missing unit!

Convert the following:

1. 330 min. hours

2. 2. 5 ft. 3 in. in.

Let’s practice!

15 days = ____ hours.

60 ft = _____ yards

100 meters = ____ centimeters

% Percents %

Percent: means out of 100How do we set up our proportion?

A few examples…

You try a few…on a post-it note!

What percent of 75 is 15?

What is 25% of 144?

20% of what number is 80?

150 percent of what number is 34?

Let’s use this strategy to help us figure out some real life situations!

A tennis racket that is normally $65 is on sale for 20% off. What is the new price of the tennis racket?

You try these two.

A dress that normally costs $38.50 is on sale for 30% off. What is the sale price?

A family sells a car to a dealership for 60% less than they paid for it. They paid $9000 for the car. What did the sell it for?

Percent ChangeTo find the percent change, we find the DIFFERENCE between the original price and the new price.

Then…..divide that by the original.

100

%

original

neworiginal

But wait! Instead of having to cross multiply by 100, we can just move our decimal two places to the right!

A coat is on sale. It originally costs $82 but it on sale today for $74.50. What is the percent discount?

How about this one?

A store buys a guitar for $295. The store then marks up the price to $340. At what percentage did the guitars price go up?

Post it Note time!1. In one year, the toll for cars to use a tunnel went

from $3 to $3.50. What is the percent change?

2. The average monthly precipitation in Chicago, Illinois, peaks in June at 4.1in. The average monthly precipitation in December is 2.8in. What is the percent change from June to December?

Homework

WORKBOOKP. 59 # 6, 7, 11, 12P. 71 # 1 – 3, 7 – 9

Study for your quiz tomorrow! (Equations with variables on both sides, proportions!)