1. Year 2 Warm-Up 1. A B CD E a.Is  AEB~  ADC? Why b.Solve for x 2 10 x 14 2. Are the two triangles similar? why? 15 18 10 12

2. Warm-Up Answers: 1.Yes, by AA (parallel lines imply congruent corresponding angles) x = 14/5 or 2.8 2. No, because the corresponding sides are not proportional.

3. 11.3 Indirect Measurement/Applications We can use similar triangles to calculate the height of tall objects that you can’t reach. This is called indirect measurement.

4. Example #1

5. Example #1 Continued Lets use what we know about similar triangles to find the height of the lamp post. 1.Set up a proportion: 2.Simplify: 3.Cross multiply: 4.Solve: x = 15 feet 9 inches

6. Example #2 8 m 12 m 9 m About how long is the log that goes across the creek?

7. Example #2 Continued Lets use what we know about similar triangles to find the length of the log 1.Set up a proportion: 2.Simplify: 3.Cross multiply: 4.Solve: The log is 6 meters

8. Classwork Option 1: Make a poster of the assigned problem with all sides labeled Set up the proportion Solve Be prepared to present to the class Problems: pg 582 1,2,3,5,7, 10 pg 614 #7,

9. Classwork Option 2: Math Lab Group Activity… Break up into groups of no more than 4 and make sure each member of your group has a math lab handout. You will need one meter stick for your group and something to write on and to write with.

10. Summary: If you were asked to find the height of this flagpole… What do you need to know to find the height? And What tools will you need?

11. Homework: 11.3 Worksheet