Question

Triangular numbers can be represented with equilateral triangles formed by dots the first fire triangle numbers are 1 3 6 10 and 15 is there a direct variation between a triangle number and its position in the sequence explain your reasoning

Answer 1

Answer:
No, the triangular numbers are not a direct variation. There is not a constant of variation between a number and it's position in the sequence. The ratios of the numbers to their positions are not equal. Also, the points (1, 1), (2, 3), (3, 6), and so on, do not lie on a line.

Explanation:

Answer 2

There's no direct variation

Explanation:

Required

Determine if there's a direct variation between the number and its position

I'll start by giving an illustration of how the triangle is represented using stars (*)

*

**

***

****

*****

Represent the line number with y and it's position with x

On line 1:

y = 1, x = 1

On line 2:

y = 2, x = 3

On line 3:

y = 3, x = 6

On line 4:

y = 4, x = 10

On line 5:

y = 5, x = 15

Note that, x is gotten by calculating the accumulated number of stars while y is the line number.

Direct variation is represented by

y = kx

Or

kx = y

Where k is the constant of variation

For line 1:

Substitute 1 for y and 1 for x

k * 1 = 1

k = 1

For line 2:

Substitute 2 for y and 3 for x

k * 3 = 2

Divide through by 3

k = ⅔

Note that the values of k in both computations differ.

This implies that there's no direct variation and there's no need to check further.