standard_description: Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so.
problem_activity: List one attribute that each of the following pairs of shapes have in common. There may be more than one correct answer.
a.   Square and rhombus
b.   Square and rectangle
c.   Square and parallelogram
d.   Square and trapezoid
e.   Square and quadrilateral


aligns: no