Question

Find the triangular number in the nth position if n is. a)22 (b)11 (c)31 (d)40​

Answer 1

a) 253

b) 66

c) 496

d) 820

Step-by-step explanation:

Triangular numbers : pattern of numbers that form equilateral triangles. Each subsequent number in the sequence adds a new row of dots to the triangle.

nth triangular number formula:
`T_n=(n(n+1))/(2)`

a) if n = 22

`T_(22)=(22(22+1))/(2)=253`

b) if n = 11

`T_(11)=(11(11+1))/(2)=66`

c) if n = 31

`T_(31)=(31(31+1))/(2)=496`

d) if n = 40

`T_(40)=(40(40+1))/(2)=820`

Answer 2

• Shown below.

Step-by-step explanation:

use the formula: n(n+1)/2

where n is the number of nth position

(a)

n(n+1)/2

22(22+1)/2

253

(b)

11(11+1)/2

66

(c)

n(n+1)/2

31(31+1)/2

496

(d)

n(n+1)/2

40(40+1)/2

820