Procedure to do activity in the simulation:
Steps to prove the property using this lab are as follows
A. Steps to draw a triangle
- Go to the TOOLS and select the triangle.
- Mark a point A on baseline to draw a triangle ABC.
- Click again on baseline for another point B.
- Click above baseline on the benchmark to mark the point C.
Triangle drawn successfully.
B. Steps to mark the interior angles and exterior angle
- Click on point A to mark ∠CAB
- Click on point B to mark ∠ABC,
- Click on point C to mark ∠ACB,
- Click on point D to mark ∠CBD(exterior angle) of triangle ABC.
C. Measure the values of resultant angles
- Drag the protractor to measure the value of the interior angles, ∠CAB and ∠ACB.
- Consider AD as a baseline for ∠CAB and line CB for ∠ACB.
- Enter the value of angles ∠CAB and ∠ACB in text box.
- Measure the value of angle ∠CBD i.e. exterior angle from base line AD.
- Enter the value in text box.
D. Verify the theorem
- Let us cut and place the interior angles on exterior angle
- Click on point A to cut angle ∠CAB.
- Click on point C to cut angle ∠ACB.
- Click on Next button to see the observation.
We observe that the interior angles completely overlap the exterior angle.
We also observe that ∠CAB +∠ACB = ∠CBD
Thus, The sum of value of interior angles ∠CAB and ∠ACB is equal to the exterior angle ∠CBD.
Hence exterior angle property of triangle is proved.