Complete the table by drawing a triangle in each cell that has the properties listed for its column and row. If you think you cannot draw a triangle with those properties, write “impossible” in the cell.

Share your drawings with a partner. Discuss your thinking. If you disagree, work to reach an agreement.

acute (all angles acute)right (has a right angle)obtuse (has an obtuse angle)scalene (side lengths all different)isosceles (at least two side lengths are equal)equilateral (three side lengths equal)Your teacher will give you a card with a picture of a triangle.

The measurement of one of the angles is labeled. Mentally estimate the measures of the other two angles.

Find two other students with triangles congruent to yours but with a different angle labeled. Confirm that the triangles are congruent, that each card has a different angle labeled, and that the angle measures make sense.

Enter the three angle measures for your triangle on the table your teacher has posted.