CBSE Class 6 Mathematics
Question 24 of 25
Patterns in Mathematics — Question 26
Back to all questions 26
Question How many little triangles are there in each shape of the sequence of stacked triangles? Which number sequence does this give? Can you explain why?
(Hint: In each shape in the sequence, how many triangles are there in each row?)
The number of little triangles in each shape of the sequence of stacked triangles is: 1, 4, 9, 16,…..
The number sequence given by this is that of perfect square numbers.
Why does this happen? The number of little triangles in each shape of the sequence of stacked triangles is a perfect square because each row has triangles in increasing order: the bottom row has n triangles, the next row up has n – 1 triangles, and so on, up to the top row that has 1 triangle. The total number of little triangles in a stacked triangle shape is a sum of increasing triangular numbers.