39 Triangles
Types of Triangles
Names by sides
Equilateral Triangle
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- All sides equal length
- All angles are equal
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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.
Watch this 4:11 video Classifying Triangles by Their Sides & Angles | Geometry | Eat Pi, May 3, 2022
Summary
- Identify different types of triangles