[size=100][size=150]1) Use the POLYGON [icon]https://www.geogebra.org/images/ggb/toolbar/mode_polygon.png[/icon] tool to construct triangle [i]ABC[/i]. [br]2) Select the RAY [icon]/images/ggb/toolbar/mode_ray.png[/icon] tool. [br] Construct a ray with endpoint [i]A[/i] that passes through [i]B[/i]. [br] Construct a ray with endpoint [i]B [/i]that passes through [i]C[/i]. [br] Construct a ray with endpoint [i]C[/i] that passes through [i]A[/i].[br][br]3) Select the POINT ON OBJECT [icon]/images/ggb/toolbar/mode_pointonobject.png[/icon] tool. [br] Plot a point [i]D[/i] on ray [i]AB[/i] that does not lie between [i]A[/i] and [i]B[/i]. [br] Plot a point [i]E[/i] on ray [i]BC[/i] that does not lie between [i]B[/i] and [i]C[/i]. [br] Plot a point [i]F[/i] on ray C[i]A[/i] that does not lie between [i]C[/i] and [i]A[/i]. [br][br]Keep going! More directions appear below this app. [/size][/size]

[size=100][size=150]4) Select the ANGLE [icon]https://www.geogebra.org/images/ggb/toolbar/mode_angle.png[/icon] tool. Then select points [i]D[/i], [i]B[/i], [i]C[/i] (in that order). This is one exterior angle of this triangle. [br][br]5) Find and display the measures of the other 2 exterior angles of this triangle. [br][br]6) Go to the ALGEBRA view. Now calculate the sum of the measures of these 3 exterior angles. [/size][/size]