standard_description: Classify two-dimensional figures based on the presence or absence of parallel or perpendicular lines, or the presence or absence of angles of a specified size. Recognize right triangles as a category, and identify right triangles.
problem_activity: Problem 1
Someone sorted some shapes as shown below.
[IMG]
a.   What is similar about the two groups of figures? What term(s) can we use to describe all of the shapes?
b.   What is different about the two groups of shapes?
Problem 2
Decide whether each of the following statements are true or false. If it is false, rewrite the statement so that it is true.
a.   A trapezoid is always a quadrilateral.
b.   A quadrilateral is never a trapezoid.


aligns: no