[b][size=150]What for?[/size][/b][br]Use the button to select a triangle congruence theorem: SSS, SAS, ASA, SAA, SSA.[br]Then specify the given triangle [color=#0000ff]sides [/color]and/or [color=#45818e]angles [/color]with either the sliders and/or input boxes. See the [color=#ff00ff]unspecified parts[/color] solved and displayed in the graphics view.[br]If the value you desire is outside the range of the sliders, enter your desired value into the input box, and the slider range will update accordingly. With a keyboard you may tab forward or shift-tab backwards between the sliders or input boxes.[br][br]The labels may be dragged so that they don't overlap the triangle geometry.[br][br]If your specified values for SSA lead to the [i]ambiguous case[/i] in which two triangles are possible, an "ambiguous" button will appear and allow you to display either one or both cases. (Also check out my GeoGebra [url=https://www.geogebra.org/m/CvtkyRM5]construction intended to explore how many triangles are formed specifically by the SSA condition[/url].)[br][br]The "labelselector" slider allows you to cycle through all possible combinations of labeling vertices/angles A, B, C and their opposite sides a, b, c respectively.[br][br][size=150][b]Zooming/Panning[/b][/size][br]This version automatically adjusts the view settings to fit the triangle. Use the + or – buttons to zoom in or out.[br][br][size=150][b]Invalid triangles?[/b][/size][br]If the triangle disappears, that means you've specified settings that do not create a real triangle. (Maybe that's obvious?) For some settings, the angle will appear external to the triangle. Such angles will exceed their respective slider values by 180°, and the sum of all displayed angles will exceed 180°. I'll leave it up to you to determine whether such triangles are valid![br]When faced with such a dubious triangle, switching between SSS, SAS, ASA, SAA, SSA may cause some sliders to disappear, but the input boxes will still be visible. Entering valid values into the input boxes will cause the sliders and triangle to re-appear.