1. 5-Minute Check on Chapter 2
Transparency 3-1
5-Minute Check on Chapter 2
Evaluate 42 - |x - 7| if x = -3
Find 4.1  (-0.5)
Simplify each expression
3. 8(-2c + 5) + 9c (36d – 18) / (-9)
A bag of lollipops has 10 red, 15 green, and 15 yellow lollipops. If one is chosen at random, what is the probability that it is not green?
Which of the following is a true statement
Standardized Test Practice: A
8/4 < 4/8 B
-4/8 < -8/4 C
-4/8 > -8/4 D
-4/8 > 4/8
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2. Lesson 11-6
Similar Triangles

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Transparency 6

4. Transparency 6a

5. Objectives Determine whether two triangles are similar
Find the unknown measures of sides of two similar triangles

6. Vocabulary
similar triangles –

7. Similar Triangles
Step 1:

8. Example 1
Determine whether the pair of triangles is similar. Justify your answer.
The ratio of sides XY to AB is
The ratio of sides YZ to BC is
The ratio of sides XZ to AC is
Answer: Since the measures of the corresponding sides are proportional, triangle XYZ is similar to triangle ABC.

9. Example 2a
Find the missing measures if the pair of triangles is similar.
Since the corresponding angles have equal measures, The lengths of the corresponding sides are proportional.

10. Example 2a cont
Corresponding sides of similar triangles are proportional.
and
Find the cross products.
Divide each side by 18.
Corresponding sides of similar triangles are proportional.
and
Find the cross products.
Divide each side by 18.
Answer: The missing measures are 27 and 12.

11. Example 2b
Find the missing measures if the pair of triangles is similar.
Corresponding sides of similar triangles are proportional.
and
Find the cross products.
Divide each side by 4.
Answer: The missing measure is 7.5.

12. Example 3
Shadows Richard is standing next to the General Sherman Giant Sequoia three in Sequoia National Park. The shadow of the tree is 22.5 meters, and Richard’s shadow is 53.6 centimeters. If Richard’s height is 2 meters, how tall is the tree?
Since the length of the shadow of the tree and Richard’s height are given in meters, convert the length of Richard’s shadow to meters.

13. Example 3 cont Simplify. Let the height of the tree. Richard’s shadow
Tree’s shadow
Richard’s height
Tree’s height
Cross products
Answer: The tree is about 84 meters tall.

14. Summary & Homework Summary: Homework:
Similar triangles have congruent corresponding angles and proportional corresponding sides.
Homework: pg