Properties of Triangles - Interior/Exterior Angles

Quick Review:
Please classify the triangles below by their [b]sides [/b]and [b]angles. [/b]DO NOT move any of the points.
Triangle ABC is an
Triangle DEF is an
Triangle GHI is an
Task One
Below you will see a triangle created with all of its [b]interior [/b]angles measured. Use this triangle to answer the following questions:
Add all three of the [b]interior[/b] angles together (including the decimals). What did you get as your answer?
Move point B and add all of them together again. What did you get this time?
What statement can we make about the [b]interior [/b]angles of [u]any[/u] triangle?
Task Two
Use the diagram below to answer the following questions:
1. What is the measure of the third angle? Hint: Imagine that (2x - 12)[math]^\circ[/math] is not there.
2. Find the value of x.
Task Three
Below you will see a triangle created with two of its [b]interior [/b]angles measured and one of its [b]exterior[/b] angles measured. Use this triangle to answer the following questions:
Add together the angle measures at point A and point B. How does this relate to the measure of the [b]exterior[/b] angle?
Move point B. What do you notice about the relationship between the two [b]interior[/b] angles and the [b]exterior[/b] angle?
What statement can we make about the relationship between the two [b]interior[/b] angles and its non-adjacent (not next to) [b]exterior[/b] angle?
Task Four
Use the diagram below to answer the following questions:
1. Find y.
2. How did you find the value of y?
3. Is there another way to find y?
Task Five
Below you will see a triangle created with all of its [b]interior [/b]angles measured with one of its [b]interior[/b] angles being 90[math]^\circ[/math]. Use this triangle to answer the following questions:
Add together the angles at point D and point C. What did you get?
Move point C. What do you get when you add together the angles at point D and point C this time?
What statement can we make about the sum (adding together) of the other [b]interior [/b]angles when [u]one[/u] of the [b]interior[/b] angles is already 90[math]^\circ[/math]?
Task Six
Use the diagram below to answer the following question:
1. Find z.
Close

Information: Properties of Triangles - Interior/Exterior Angles