Triangle Angle Sum Theorem (V4)
In the applet below, note the triangle and its 3 large white vertices. [br][br]You can move the vertices anywhere you'd like at any time. [br][b][color=#ff00ff]The pink slider controls the size of the (soon-to-appear) pink angle. [/color][/b] [br][br]Interact with this resource for a few minutes. As you do, be sure to move the vertices of the triangle around each time before re-sliding the slider. [br][br]Please answer the question that follows.
1.
What can we conclude about the [b]SUM[/b] of the measures of the [b][color=#ff00ff]pink angle[/color][/b], [b][color=#1e84cc]blue angle[/color][/b], and [color=#38761d][b]green angle[/b][/color] (i.e. the 3 interior angles) of this triangle?
Quick (Silent) Demo
Triangle Exterior Angle
[color=#000000]In the app below, an [b]exterior angle of a triangle[/b] is shown.[br]The 2 colored angles[/color][color=#000000] are referred to as its [/color][i]remote interior angles. [/i]
Interact with this app for a few minutes. LARGE POINTS are moveable.
[color=#000000]What can we conclude about the measure of an exterior angle when we compare it to its remote interior angles? Explain. [/color]
What other theorem is readily made obvious here?