Questions 1–3 refer to the triangles shown above.

1. How many sides (edges) does each triangle have?
2. A point where two sides come together is called a vertex. Vertices are at the corners. How many vertices does each triangle have?
3. How many right angles (square angles) does each triangle have? (Hint: compare each angle in a triangle with a corner of a square tangram piece or a piece of paper.)
4. A shape has line symmetry if you can fold it in half so that the halves match exactly. The fold line is called a line of symmetry. How many lines of symmetry does the following shape have? Sketch the shape and show the lines of symmetry.