1.11. Triangle Classification http://www.ck12.org
Note that by the above definitions, an equilateral triangle is also an isosceles triangle.
Example A
Which of the figures below are not triangles?
Bis not a triangle because it hasone curved side.Dis not a closed shape, so it is not a triangle either.
Example B
Which term best describes 4 RSTbelow?
This triangle has one labeled obtuse angle of 92◦. Triangles can only have one obtuse angle, so it is an obtuse
triangle.
Example C
Classify the triangle by its sides and angles.