What is the 100th triangular number?
2006-12-19 12:08:47 · 3 answers · asked by i_fab2 2 in Science & Mathematics ➔ Mathematics
A triangular number is a natural number such that the shape of an equilateral triangle can be formed by that number of points. Every triangle number can be written as the sum 1 + 2 + 3 + ... + n for some natural number n. The sequence of triangular numbers (sequence A000217 in OEIS) for n = 1, 2, 3... is:
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
The formula for the nth triangular number is:
N*(N+1)/2
so the 100th triangular number is
100*101/2 = 50*101 = 5050
2006-12-19 12:12:32 · answer #1 · answered by firefly 6 · 1⤊ 0⤋
The nth Triangular Number is the sum of integers from 1 to n. So the 100th Triangular Number is the sum of numbers from 1 to 100, which is 5050.
2006-12-19 12:24:30 · answer #2 · answered by hpuew 1 · 0⤊ 0⤋
ANS : 5050
This site will show you all 100 triangular numbers
http://www.mathematische-basteleien.de/triangularnumber.htm
2006-12-19 14:19:58 · answer #3 · answered by Sherman81 6 · 0⤊ 0⤋