[b]Background[/b][br]If the sum of the degrees of two angles is 90 degrees then the two angles are said to be [i][b][color=#ff0000]complimentary[/color][/b][/i].[br][br][b]Step 1. Predict[/b][br]On paper, make a Report Table like this:[table][tr][td][u]Angle 1[/u][/td][td][u]       Angle 2      [/u][/td][td][u]     Check with Protractor    [/u][/td][/tr][tr][td]23 degrees[/td][td][/td][td][/td][/tr][tr][td]45 degrees[/td][td][/td][td][/td][/tr][tr][td]12 degrees[/td][td][/td][td][/td][/tr][tr][td]81 degrees[/td][td][/td][td][/td][/tr][tr][td]64 degrees[/td][td][/td][td][/td][/tr][/table][br]In the Angle 2 column, [u][i]without using the protractor[/i][/u], write the size of the angle that you think will be [i][b][color=#ff0000]complimentary [/color][/b][/i]to Angle 1.[br][br][b]Step 2. Check Your Prediction[/b][br]On the [i]GeoGebra [/i]page, use the MOVE tool [icon]/images/ggb/toolbar/mode_move.png[/icon]to move Point B and change the [br]size of the angles ECB and BCA.  [br][br]Set either one of these angles to the value for Angle 1 given in the Report Table and check to [br]see if the [i][b][color=#ff0000]compliment [/color][/b][/i]is what you predicted.  [br][br]If it is, place a check mark in the Check with Protractor column.  [br][br]If it is not, write in the size of the actual [b][i][color=#ff0000]complimentary [/color][/i][/b]angle in degrees.