Background
If the sum of the degrees of two angles is 90 degrees then the two angles are said to be complimentary.
Step 1. Predict
On paper, make a Report Table like this:
Angle 1
Angle 2
Check with Protractor
23 degrees
45 degrees
12 degrees
81 degrees
64 degrees
In the Angle 2 column, without using the protractor, write the size of the angle that you think will be complimentary to Angle 1.
Step 2. Check Your Prediction
On the GeoGebra page, use the MOVE tool to move Point B and change the
size of the angles ECB and BCA.
Set either one of these angles to the value for Angle 1 given in the Report Table and check to
see if the compliment is what you predicted.
If it is, place a check mark in the Check with Protractor column.
If it is not, write in the size of the actual complimentary angle in degrees.
to move Point B and change the
size of the angles ECB and BCA.
Set either one of these angles to the value for Angle 1 given in the Report Table and check to
see if the compliment is what you predicted.
If it is, place a check mark in the Check with Protractor column.
If it is not, write in the size of the actual complimentary angle in degrees.