1. ∆JKL ∼ ∆MNO with a scale factor of 5:6
∆JKL ∼ ∆MNO with a scale factor of 5:6. If MN = 3x and JK = x + 15, find the value of x.
Problem of the Day

2. Section 7-3 Similar Triangles

3. Then
Now
Objectives
You used AAS, SSS, and SAS Congruence Theorems to prove triangles congruent.
Identify similar triangles using the AA Similarity Postulate and the SSS and SAS Similarity Theorems.
Use similar triangle to solve problems.

4. Common Core State Standards
Content Standards
G.SRT.4 – Prove theorems about triangles.
G.SRT.5 – Use congruence and similarity criteria for triangles to solve problems and to prove relationships in geometric figures.
Mathematical Practices
4) Model with mathematics.
7) Look for and make use of structure.
Common Core State Standards

6. Determine whether the triangles are similar
Determine whether the triangles are similar. If so, write a similarity statement. Explain your reasoning.
Example 1

7. Determine whether the triangles are similar
Determine whether the triangles are similar. If so, write a similarity statement. Explain your reasoning.
Example 1

8. Determine whether the triangles are similar
Determine whether the triangles are similar. If so, write a similarity statement. Explain your reasoning.
Example 1

10. Determine whether the triangles are similar
Determine whether the triangles are similar. If so, write a similarity statement. Explain your reasoning.
Example 2

11. Determine whether the triangles are similar
Determine whether the triangles are similar. If so, write a similarity statement. Explain your reasoning.
Example 2

12. Adam is standing next to the Palmetto Building in Columbia, South Carolina. He is 6 feet tall and the length of his shadow is 9 feet. If the length of the shadow of the building is feet, how tall is the building?
Example 4

13. Josh wanted to measure the height of the Willis Tower
Josh wanted to measure the height of the Willis Tower. He used a 12 ft light pole and measure its shadow at 1PM. The length of the shadow was 2 ft. Then he measure the length of the Willis Tower’s shadow and it was 242 ft at the same time. What is the height of the Willis Tower?
Example 4

14. A lighthouse casts a 128 ft shadow
A lighthouse casts a 128 ft shadow. A nearby lamppost that measures 5 ft 3 in casts an 8 ft shadow. What is the height of the lighthouse?
Example 4

15. p.483 #1 – 4, 6 – 8, 22, 23, 52
Homework