Lesson 2 of 15
Named by its sides
Show on a big screenA teacher sorts paper triangles for the notice board. Some have sides of equal length. Some do not.
Count the matches
Measure all three sides. Count how many lengths match. That count gives the name.
| Sides that match | Name | Example, in mm |
|---|---|---|
| All three | Equilateral | 60, 60, 60 |
| Exactly two | Isosceles | 26, 26, 48 |
| None | Scalene | 30, 40, 50 |
Turning a triangle changes no length. So its name does not change.
Move the top corner. Make two sides equal. Then make all three equal.
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Try the lab to finish this lesson.