Applet for demonstrating that a triangle with ASA defined is "rigid" when moved.
Construction Instructions:
Do the following, loosely in the following order.
i. Create a point A and a line.
ii. Define the length AD=423.5 and the angles EAD=63 and ADE=80.
iii. Create a circle with radius AD and find where it intersects the line.
iv. Create an angle rising ADE degrees clockwise from DA to form angle ADE.
v. Create an angle rising DAE degrees counterclockwise from AD to form angle DAE.
vi. Add lines AD’ and DA’.
vii. Add point E at the intersection of those lines. (Zoom out as necessary).
viii. Move points A and B to see if triangle is rigid.
ix. Measure length AE.
x. If desired, color-coordinate the sliders with the parts of the triangle they control.
