GeoGebra Classroom

2.5 Angle Relationships

Investigation #1

1. Use the angle tool to measure one linear pair of angles in the diagram below. 2. Use the arrow tool the click and drag point D to change the angle measures. 3. Complete the questions below the figure based on your observations.

Observation

Which of the following statements is always true about the linear pair of angles?

Select all that apply
• A
• B
• C
• D

C-1 The Linear Pair Conjecture

If two angles form a linear pair, then they are _____.

Select all that apply
• A
• B
• C
• D

Investigation #2

1. Use the arrow tool to select and then delete one of your 2 angle measures. 2. Use the angle tool to measure the angle that is vertical to the angle measure that is left. 3. Click and drag point D to change the angle measures. 4. Complete the questions below based on your observations

Observation

Which of the following statements is always true about the pair of vertical angles?

Select all that apply
• A
• B
• C
• D

C-2 Vertical Angles Conjecture

If two angles are vertical angles, then they are _____.

Select all that apply
• A
• B
• C
• D