1. Warmups
A tree casts a shadow 8 feet long. At the same time, a flagpole 10 feet tall casts a shadow 15 feet long. How tall is the tree?
Find I, if p = $950, r = 9%, t = 6 months
Find r, if I = $912, p = $7600, t = 4 years

2. 4-5 Percent of Change
Objective: To solve problems involving percent of increase or decrease.

3. Percent of Change
Percent Increase: new amount/price goes up
Percent Decrease: new amount/price goes down
Example 1: Mac reduced the price of the nano ipod from $179 to $139. What is the percent decrease?
Amount of decrease = _x_
Original #
(Big # - small #)

4. Another method 
You can also divide the fraction in your calculator and then change the decimal to a percent: (do example 1 with this method)

5. Example 2
Ms. Lundblad’s groovy math club on campus had 56 members last year. This year there are 137 members. What is the percent increase?

6. Try with a Partner new: $98 new: 289 people
Increase or decrease? Round to nearest whole percent
3. original: $ original: 322 people
new: $ new: 289 people

7. TOO new: $230 6. Find t, if I = $1400, r = 7%, p = $625 Answers:
5. original: $212
new: $230
6. Find t, if I = $1400, r = 7%, p = $625
Answers:
8% increase
32 years

8. Homework
Pg. 225 #12-20 All

9. Math Lab Warmups
A tree casts a shadow 6 feet long. At the same time, a flagpole 9 feet tall casts a shadow 21 feet long. How tall is the tree?
Find I, if p = $650, r = 3%, t = 9 months
Find r, if I = $250, p = $5400, t = 4 years

10. ZONK TIME!!
Everything away
Whiteboard, sock, marker..
GOOOOOO!