# Interior/Exterior Angles of Triangle

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This pdf includes the following topics:-
Types of Angles
Triangle Sum Theorem
Exterior Angle Theorem
1. Math Virtual Learning
Interior/Exterior Angles of a Triangle
April 10, 2020
Lesson: April 10
Learning Target:
Student will identify interior and exterior angles of a
triangle.
Lesson Includes:
1) Angle Types
2)Triangle Sum Theorem
3) Exterior Angle Theorem
3. Warm Up Activity
On a piece of paper, identify the following angles.
Review the questions from the previous slide.
Acute Right Obtuse Acute
5. Instruction: Types of Angles
Read through the vocabulary and review the diagrams. Then watch the
1) Interior Angle: an angle inside a shape
2) Exterior Angle: is an angle outside of a shape, made
by the side of a shape and a line drawn out from an
3) Acute Angle: an angle that’s less than 90 degrees
4) Obtuse Angle: an angle that is greater than 90
5) Right Angle: a 90 degree angle
6) Complementary Angle: two angles that when added
together equal 90 degrees Today we are
7) Supplementary Angle: two angles that when added
mainly focusing on
Interior and
together equal 180 degree Exterior Angles!
6. Practice: Types of Angles
On a piece of paper: Identify the exterior and interior angles shown in the
problems.
1) 2)
3) 4)
7. Practice: Types of Angles ANSWERS
On a piece of paper: Identify the exterior and interior angles shown in the
1) 2)
3) 4)
8. Instruction: Triangle Sum Theorem
Read through the theorem and steps. Watch the provided video here. Then
review the examples on the next slide.
The triangle sum property states that the sum of the three
interior (inside the triangle) angles in a triangle is always
180 degrees.
1) Write an equation that adds all three angle
2) Set the equation equal to 180 degrees.
3) Solve for the variable.
4) Plug the value of the variable (the answer) back into any Don’t forget your steps
angle expression that you need to find the value of. for solving equations!
9. Instruction: Triangle Sum Theorem
Review the examples. Directions: Solve for the variable, then find the missing
angle(s).
10. Practice: Triangle Sum Theorem
On a piece of paper: Solve for the variable, then find the missing angle(s).
Question 1 Question 2
Question 3
11. Practice: Triangle Sum Theorem Answers
slide.
Question 1
Question 3
Question 2
12. Instruction: Exterior Angle Theorem
Read through the theorem and steps. Watch the provided video here. Then
review the examples on the next slide.
The measure of an exterior angle of a triangle is
equal to the sum of the measures of the two
remote interior angles.
What if you are not given all the angles?
1) Write an equation: remote interior angle +
remote interior angle = exterior angle
2) Solve for the variable.
3) Plug the value of the variable (the answer) back
into any angle expression that you need to find the
value of.
13. Instruction: Exterior Angle Theorem
Review the examples.
14. Practice: Exterior Angle Theorem
On a piece of paper: Solve for the variable, then find the missing angle(s).
3.
15. Practice: Exterior Angles Theorem Answers