Triangular Number
A number that can make a triangular dot pattern. Each side in the triangle containes the same number of dots.
- 1 = 1 dot
 - 2 = 3 dots
 - 3 = 6 dots
 - 4 = 10 dots
 - 5 = 15 dots
 - etc.
 
A number that can make a triangular dot pattern. Each side in the triangle containes the same number of dots.