All three angles must add up to 180˚. Label the angles with a variable and form an equation that is equal to 180˚. An isosceles triangle has two equal sides. These are shown by the hatch marks.

Students may notice symmetry in the isosceles and equilateral triangles and non-symmetry in the scalene triangles Informal recognition of these properties may be helpful in recognizing formal ...

Students may notice symmetry in the isosceles and equilateral triangles and non-symmetry in the scalene triangles Informal recognition of these properties may be helpful in recognizing formal ...