# Question #1d0d6

##### 2 Answers

Also see part 2 of 2 for the calculation method

If you use a strait line of best fit you can not be precise enough to satisfactorily predict values.

#### Explanation:

Triangular numbers are constructed as in the diagram.

You add up all the dots from the first one down to whichever point you wish to stop.

The

See part 1 of 2 first before reading this one.

#### Explanation:

The sequence is

Notice that the last value in the sum is the term number or line number.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Consider any one of the rows

Let the first value be

Let the last value be

Then the sum of any row is

count

but

Changing the order we have:

Compare this to the standardised equation of a quadratic

so if