standard_description: Prove theorems about triangles. Theorems include: measures of interior angles of a triangle sum to 180°; base angles of isosceles triangles are congruent; the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length; the medians of a triangle meet at a point.
problem_activity: The two triangles in the picture below are congruent:
[IMG]
a.   Give a sequence of rotations, translations, and/or reflections that take
$${\triangle PRQ}$$
to
$${\triangle ABC}$$
.
b.   Is it possible to show the congruence in part (a) using only translations and rotations? Explain.


aligns: no