Question

EASY geometry!!
Please help I’ve been stuck on this for too long and it’s due tomorrow :(

Answer 1

{n*(n+1) } /2

Explanation:

The clearest pattern is that the last digit is multiplied by the number after it and then the multiplication is divided by 2.

1 is multiplied by 2, then divided by 2.

2 is multiplied by 3, then divided by 2.

3 is multiplied by 4, then divided by 2.

So, the pattern is:

{n*(n+1) }/2.

Hope this helped!