You are given two congruent triangles that have the same orientation. Using GeoGebra's tool, build a single rotation that takes the green triangle to the blue triangle.

Before you do anything:

Why can't the single move be a translation?

Why can't the single move be a reflection?

Play a little:

Triangle ABC is the original triangle. See what happens when you change the lengths of the sides on triangle ABC.

Point D is fixed. You can rotate triangle DEF around D by moving point E.

Use the mouse to see that triangle DEF is indeed congruent to triangle ABC.

Use the upper right-hand corner reset icon, so that the triangles are back in their original position.

Find the Rotation

Using GeoGebra's tools, find a point and an angle that will define the rotation that takes poly2 to poly1.

Note that the first angle you define will be called . You can type an alpha by holding the alt key
while pushing the a key.

Make sure that your rotation continues to work when you move