Question

Hi, i'd really appreciate it if someone answere this :)

Answer 1

12th triangular number is 78

50th triangular number is 1275

Explanation:

12+1=13

12÷2=6

6x13=78

if you do this for 50 you get 1275

Answer 2

Explanation:

12 number

Wherever you see an n put in 12

12 (12 + 1)/2

12 * 13 / 2

6 * 13

78

The 12th triangular number is 78

50th triangular number

Again, wherever you see an n put in 50

n/2 * (n+ 1)

50/2 * (50 + 1)

25 * 51

1275