# Grade 9 Algebra Question 3

posted by
**Jab** on
.

TRIANGULAR NUMBERS By arranging

bowling pins in their proper order, a

triangle is created. The table below

shows the number of rows of bowling

pins and the total number of pins in the triangle. The formula:

n * (n+1) / 2

can be used to find t, the total number of items in n rows. How many bowling pins would there be if 10 rows of pins were set up?

Rows 1 2 3 4

Pins 1 3 6 10