[size=150]1) Use the POLYGON [icon]/images/ggb/toolbar/mode_polygon.png[/icon] tool to construct triangle [i]ABC[/i]. [br]2) Select the ANGLE [icon]/images/ggb/toolbar/mode_angle.png[/icon] tool. Then click anywhere inside the polygon. [br]3) Go to the Algebra view (click calculator icon upper left). [br][br]4) Calculate the sum of the measures of the interior angles of this triangle. [br] (Start at 0:38 in video at the bottom if you're unsure of how to do this in GeoGebra). [br][br]Keep going! There's a question below the app here. [/size]
[size=150]Select the MOVE [icon]/images/ggb/toolbar/mode_move.png[/icon] tool. Move any one (or more) of the triangle's vertices around. [br]What can we conclude about the [b]sum of the measures of the interior angles of this triangle[/b]? [i]Be specific in your response! [/i][/size]