ran a javascript program instead of using math and found that 10,000,001 isn't a triangle number, these are the ones right before and after it:
997578
998991
1000405
1001820
10000001
129 = 10000001
10000001
10000001
10000001 times
28 is a triangle number. The 28th triangle number is 406.
The third triangle number is 6.
The binary representation of the keyword "129" in decimal is 10000001.
The fifth triangle number, known as T5 is 15.
No. Triangle numbers are a fixed set of numbers that can't be altered to make one certain number turn into a triangle number.
A triangular number or triangle number counts the objects that can form an equilateral triangle. 10 objects can be formed into an equilateral triangle.
The area of a triangle can be a rational number or an irrational number depending on its dimensions.