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GeoGebraGeoGebra Classroom

Unit 4 Interior & Exterior Angles of Triangles-DISCOVERY

Step 1) Click the TRIANGLE BUTTON to create triangle A, B, C, Step 2) Click the Text Button to label the vertices ABC

Interior Angle Sum

Step 3) Click the ANGLE BUTTON, and Click to find all 3 interior angles of your triangle. Record the measure for each angle m

Step 4) Find the sum of the three angles. Record your answer here.

Step 5) Switch up your triangle!Click the arrow button (which allows you to move a vertex) Drag each vertex and change the angle measurements. As you change the Triangle's interior angles, what do you notice about the sum of all 3 angles? (THEY ALWAYS ADD UP TO......)

Step 5 Challenge: Try to create Whole Number Integers (No Decimal) angle measurements! It's not easy! How many interior angle measurements were you able to create without Decimals?

Select all that apply
  • A
  • B
  • C
Check my answer (3)

The Angle Sum Theorem states: The sum of the measures of the angles in a triangle is ______ Please refer to pg. 4 in your notes if needed!

Step 6) Using the new Triangle ABC, Find the Tool To measure ALL THE INTERIOR ANGLES.

Step 6) Click the Angle Measure Button, then click the INSIDE of the triangle, find ALL interior angle measurements. Write down all the measurements on your paper, find the measure of Angle A 

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Step 7) Find the m< C

Select all that apply
  • A
  • B
  • C
Check my answer (3)

The Sum of the Two Remote Interior= Exterior

Step 8) Find the sum of m< A + m < C= Exterior Angle

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Step 10) Exterior Angles: Angles on the Outside of the triangle Find the measure of EXTERIOR ANGLE <DBC

130 degrees

Step 9) Exterior Angles: Angles on the Outside of the triangle Find the measure of EXTERIOR ANGLE <DBC (Click the measuring icon, and click Vertex D, B and Then C)

Step 10) What is another way you could find the measure of Angle DBC? *Think Supplementary

Step 11) FInd the measurements of the other two EXTERIOR Angles using the angle measurement tool. What do you notice? Write measurements down.