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2024-2025 Sum of Angles of Triangle

Author:Addison Bean, Andy Talmadge, Tim Brzezinski, Jill Casey, Rachel Vieira, Anthony DiLaura
Use the graphic to discover the sum of the angles of a triangle. Make three different triangles and record the angles on your paper. After you make three different triangles and record their angles on your paper, complete questions 1-5.

Now that you have looked at the diagrams, it is time to answer Questions 1-5

Do your best to answer the questions using your observations.

ACTUAL NOTES!!! Fill in the blanks at the bottom of the page

When a line is continued through a triangle, the ANGLE on the outside of the triangle is called an EXTERIOR ANGLE.

Notes! Fill in the blank! ANOTHER ONE DO NOT MISS IT

The exterior angle is EQUAL to the SUM of the two non-adjacent INTERIOR angles. Below is another view of how these angles and the exterior angle are related.

BIG TAKE AWAYS

BIG TAKE AWAYS
You may write these anywhere on your notes if you find them helpful. 1st - All the angles in a triangle add to 180 degrees. (In the picture: 30 + 70 + 80 = 180) 2nd - A linear pair adds to 180 degrees. If an angle is in a triangle and sitting on a straight line it can become a linear pair with the exterior angle. (In the picture: x and 80 degrees) So if 80 is one of the angles and it should equal 180 with its exterior angle, then the exterior angle is 100 (so 180 - 80 = 100). Guess what! The two other angles in that triangle are 70 and 30! Well 70 + 30 = 100 also! THUS, the exterior angle should equal the sum of the other two angles in the triangle!

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