Find the value of each expression mentally.

1. From the set of triangle cards, find all the triangles that have each attribute. Record their letter names here.

   

   Table. 3 rows, 3 columns. First row. a. No right angles. b. parallel sides. c. perpendicular sides Second row. d. The same length for all sides. e. the same size for all angles. f. more than one right angle. Third row. g. More than one obtuse angle. h. more than one acute angle. i. foldable into two equal halves.

2. Choose 1 sentence to complete based on your work.

   1. I noticed that some triangles . . .
   2. I noticed that all triangles . . .
   3. I noticed that no triangles . . .

1. Identify all shapes that are right triangles. For each right triangle, mark the right angle with a small square.

   

   8 shapes. A. 3 sides, two equal sides, 3 acute angles. B. 4 sides, 1 pair of parallel sides, 2 right angles. C. 3 sides. 1 right angle, 2 acute angles. D. 3 sides. 2 equal sides, 1 right angle. E. 3 sides, 3 equal sides, 3 acute angles. F. 4 sides, 1 pair of parallel sides, 2 acute angles and 2 obtuse angles. G. 3 sides, 1 right angle, 2 acute angles. H, 3 sides, 3 acute angles.

2. Explain why the other shapes are not right triangles.