If two angles and the included side of one triangle are congruent to the[br]corresponding parts of another triangle, the triangles are congruent.[br][br][b][color=#0000ff]The "included side" in ASA is the side between the angles being used. It is the[br]side where the rays of the angles overlap.[/color][/b][br][br]Below is an example how to construct this. If you change anything in the[br]construction, just click on the arrows on the top right to restore the[br]construction.

[b][center][color=#ff0000]Now you try to draw a triangle congruent to the previous one[br][/color][br][color=#38761d]You need to draw a triangle with side AB=8cm included between an angle CAB of 40 degrees and angle CBA of 30 degrees. Try to do this in the "Applet" below[/color][/center][/b][br] [br][list=1] [*]Use [icon]/images/ggb/toolbar/mode_segmentfixed.png[/icon] to draw segment AB and if you are requested to give the length type in 5[/*] [*]Use  [icon]/images/ggb/toolbar/mode_anglefixed.png[/icon] to draw an angle at point A. ([color=#0000ff][b]Hint: Always click last on the point where you want the angle.[/b][/color]) If requested for the angle size type in 40 degrees. Lastly you need to select clockwise or counterclockwise. The direction of movement is from the line in a clockwise or counterclockwise direction.[/*] [*]Use [icon]/images/ggb/toolbar/mode_ray.png[/icon] to draw a ray from point A through point B' that were created by the angle tool.[/*][*]Use  [icon]https://tube.geogebra.org/images/ggb/toolbar/mode_anglefixed.png[/icon] to draw an angle at point B. If requested for the angle size type in 30 degrees.[/*][*]Use [icon]https://tube.geogebra.org/images/ggb/toolbar/mode_ray.png[/icon] to draw a ray from point B through point A' that were created by the angle tool.[/*][*]Use [icon]/images/ggb/toolbar/mode_intersect.png[/icon] to place point C at the intersection of the two rays[br][/*] [*]Use [icon]/images/ggb/toolbar/mode_polygon.png[/icon] to draw triangle ABC[/*][/list]