1. A radio tower casts a shadow 8 ft long at the same time that a vertical yardstick casts a shadow half an inch long. How tall is the radio tower?
Problem of the Day

2. Section 7-4 Parallel Lines and Proportional Parts

3. Then
Now
Objectives
You used proportions to solve problems between similar triangles.
Use proportional parts within triangles.
Use proportional parts with parallel lines.

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
1) Make sense of problems and persevere in solving them.
3) Construct viable arguments and critique the reasoning of others.
Common Core State Standards

6. Find the value of x.
Example 1

7. Find the value of x.
Example 1

8. Midsegment of a Triangle: a segment with endpoints that are the midpoints of two sides of the triangle.
Vocabulary

10. 𝐽𝐻 and 𝐻𝑁 are midsegments of △KLM. Find the value of x.
Example 3

11. 𝐽𝐻 is a midsegment of △KLM. Find the value of x.
Example 3

13. Frontage is the measure of a property’s boundary that runs along the side of a particular feature such as a street, lake, ocean, or river. Find the ocean frontage for Lot A to the nearest tenth of a yard.
Examples 4 & 5

14. If QT = x + 6, SR = 12, PS = 27, and TR = x - 4, find QT and TR.
Examples 4 & 5

15. Find x.
Examples 4 & 5

16. p.495 #11, 13, 20 – 22, 24, 25, 35 – 38, 57
Homework