Triangle Basics Lesson

Unit 4: Triangles

Notes: Pg 44-47​

During this lesson, you will complete notes and practice for each section.

P.S.... THIS IS A GRADE!​

Important Information:

• There are 3 angles, 3 sides (line segments), and 3 vertices (corners).

• The angles of a triangle add up to 180 degrees.

• You name a triangle using the 3 vertices.

​Triangle Basics: Complete the following notes on Pg. 44.

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Multiple Select

Select all the possible names for this triangle.

• $$\Delta PQR$$  

• $$\Delta QR$$  

• $$\Delta P$$  

• $$\Delta QPR$$  

• $$\Delta RPQ$$  

Multiple Choice

If $$m\angle E$$  is $$23\degree$$ and the $$m\angle G$$  is $$23\degree$$ , what is the $$m\angle F$$  ?

• $$m\angle F\ =\ 23\degree$$  

• $$m\angle F\ =157\degree$$  

• $$m\angle F\ =\ 134\degree$$  

Important Information:

• You can classify a triangle based on its angles and/or its sides.

• Pay close attention to the markings on each type of triangle.

• A dash through the sides shows that those sides have the same measure.

​Classifying Triangles: Complete the following notes on Pg. 45.

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Multiple Choice

Classify this triangle by its sides.

• Equilateral Triangle

• Scalene Triangle

• Isosceles Triangle

Multiple Choice

Classify this triangle by its angles.

• Acute Triangle

• Obtuse Triangle

• Right Triangle

• Equiangular Triangle

Multiple Choice

Classify this triangle by its angles.

• Acute Triangle

• Obtuse Triangle

• Right Triangle

• Equiangular Triangle

Multiple Select

Classify this triangle by its angles.

• Acute Triangle

• Obtuse Triangle

• Right Triangle

• Equiangular Triangle

Multiple Choice

Classify this triangle by its sides.

• Equilateral Triangle

• Scalene Triangle

• Isosceles Triangle

Multiple Choice

Classify this triangle by its sides.

• Scalene Triangle

• Isosceles Triangle

• Equilateral Triangle

Important Information:

• The 3 angles HAVE TO EQUAL 180 degrees!

​Angle Theorems Part 1: Complete the following notes on Pg. 46.

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Important Information:

• Both triangles are congruent, therefore the matching angles are also congruent.

​Angle Theorems Part 1: Complete the following notes on Pg. 46.

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Multiple Choice

Using the Angle Sum Theorem, find the $$m\angle1$$ . 

• $$24\degree$$  

• $$37\degree$$  

• $$119\degree$$  

• $$180\degree$$  

Multiple Choice

Using the Angle Sum Theorem, find the $$m\angle1$$ . 

• $$61\degree$$  

• $$68\degree$$  

• $$51\degree$$  

• $$180\degree$$  

Important Information:

• To get the exterior angle, just add the two angles furthest away.

​Angle Theorems Part 1: Complete the following notes on Pg. 47.

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Important Information:

• If two sides are congruent, two angles will be as well.

​Angle Theorems Part 1: Complete the following notes on Pg. 47.

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Multiple Choice

Using the Exterior Angle Theorem, find the $$m\angle1$$ . 

• $$76\degree$$  

• $$52\degree$$  

• $$128\degree$$  

• $$180\degree$$  

Multiple Choice

Using the Exterior Angle Theorem, find the $$m\angle1$$ . 

• $$104\degree$$  

• $$79\degree$$  

• $$25\degree$$  

• $$183\degree$$  

Multiple Choice

Using the Isosceles Triangle Theorem, find the $$m\angle J$$ . 

• $$68\degree$$  

• $$112\degree$$  

• $$44\degree$$  

​Assignment - IXL F.2 and F.3

These are due by Monday ​10/24/22

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