its like a pattern.
2006-09-19 11:45:09 · 4 answers · asked by dorkified at heart 1 in Science & Mathematics ➔ Mathematics
Just "google" that phrase and you will see pictures of points on triangles which show you why they are called triangular numbers
2006-09-19 11:48:28 · answer #1 · answered by MollyMAM 6 · 0⤊ 0⤋
Triangular numbers are so named because numbers of this form can be arranged in the shape of an equilateral triangle. More specifically, the triangular number is a figurate number that can be represented in the form of a triangular grid of points where the first row contains a single element and each subsequent row contains one more element than the previous one.
The sequence of triangular numbers for n = 1, 2, 3... is:
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
Since each row is one unit longer than the previous row it can be seen that a triangular number is the sum of consecutive integers.
The formula for the nth triangular number is ½n(n + 1) or (1 + 2 + 3 + ... + [n − 2] + [n − 1] + n).
REFERENCES:
1.http://en.wikipedia.org/wiki/Triangular_number
2.http://mathworld.wolfram.com/TriangularNumber.html
2006-09-19 21:03:54 · answer #2 · answered by K Sengupta 4 · 0⤊ 0⤋
The numbers come from a division in a side of a rectangular triangle... Pythagoras.
They can be find by the formula: f(n) = n(n+1)/2 , n=1,2,3,4...
the sequence is 1,3,6,10,...
2006-09-19 11:53:36 · answer #3 · answered by vahucel 6 · 0⤊ 0⤋
For example think of ten bowling pins in a triangle, or fifteen billiard balls at the beginning of a game of pool. They make a nice triangle.
2006-09-19 11:54:45 · answer #4 · answered by banjuja58 4 · 0⤊ 0⤋