Types of Triangles

Names by sides

Equilateral Triangle

• • • • • All sides equal length
        • All angles are equal

The little lines that cross the sides are called “tick marks”, “hatch marks”, or “hash marks”.

Each side with one tick mark means that the sides are equal.

Each angle has a little curved line across it. Angles with the same curved lines are also equal.

Isosceles triangles

• Two sides equal length
• Two angles are equal

Tick marks at not always used.

Scalene triangles

• No equal sides
• No equal angles

Notice here that each line has a different number of tick marks.  Each line has a different measurement that the other two.

Notice the angles each have a different number of curved lines across them. None of the angles equal one another.

Right-angle triangles

• One right angle

Right triangles will usually have that little box in the corner.  Most of the time the 90-degree number is not included.

Summary

• Identify different types of triangles