Answer:
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: [tex]T_n=\dfrac{n(n+1)}{2}[/tex]
a) if n = 22
[tex]T_{22}=\dfrac{22(22+1)}{2}=253[/tex]
b) if n = 11
[tex]T_{11}=\dfrac{11(11+1)}{2}=66[/tex]
c) if n = 31
[tex]T_{31}=\dfrac{31(31+1)}{2}=496[/tex]
d) if n = 40
[tex]T_{40}=\dfrac{40(40+1)}{2}=820[/tex]
