TOPICObjective To use angles to tell whether triangles are similar Essential Question How can you use angles to tell if triangles are similar Example The triangles have two pairs of congruent angles ID: 547287
Download Presentation The PPT/PDF document "Lesson 3.4" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Lesson 3.4
TOPIC/Objective: To use angles to tell whether triangles are similar.
Essential Question: How can you use angles to tell if triangles are similar. Slide2
Example:
The triangles have two pairs of congruent angles.
The 3
rd
angle in each triangle must be 55⁰, therefore the triangles are similar. Slide3
Example:
Solve for x and y in each triangle
63 + 63 +
y
= 180
126 +
y
= 180
y
= 54
Both triangles have angles of 54, 63, 63
SimilarSlide4
Example:
38 + y + 90 = 180
128 + y = 180
y = 52
90, 42, 48
38, 52, 90
Only one angle is the same.
Not SimilarSlide5
Example:
You place a mirror on the ground 6 feet from the lamppost. You move back 3 feet and see the top of the lamppost in the mirror. You are 5 feet tall.
What is the height of the lamppost?
The triangles are similar because two angles are the same, making all angles the same.
3ft
6ft
5ft
3x = 30
X = 10
The light pole is 10 ft. tall