First, students in Ms. Elder's class had to determine the angle measurements of all of the pattern blocks. They started with the angles they knew: those of the square are 90 degrees. They could then figure out the other angles using various strategies. They used their knowledge of the measurement of a straight line (180 degrees) to find the measurement of some of the angles. Looking at the student work on the left, consider how students figured out the measurement of the smaller angle of the red trapezoid and the measurement of the angles of the triangle. After reasoning the angles of each of the pattern blocks, students can check the measurements with a protractor.

After determining the measurements of the angles, the students then rotated the pattern blocks around a point. They marked the measurement of each of the angles that touched the point. They then filled in the chart. When they added up all of their angles, they measured 360 degrees, a complete circle. Students can also classify angles as acute, obtuse and right, combining several indicators.