In a school, pupils were told to design a series of patterns with triangles and squares. Luis's group came up with the following series of patterns.
- How many squares did Luis's group need to form pattern 17?
- How many triangles did Luis's group need to form a pattern with 25 squares?
(a)
Patterns for the number of triangles and squares
Pattern 1: 1 triangle 5 squares
Pattern 2: 2 triangles 9 squares
Pattern 3: 3 triangles 13 squares
Formula:
Number of triangles = Pattern number
Pattern for the number of squares
Pattern 1: 1 + 1 x 4 = 5
Pattern 2: 1 + 2 x 4 = 9
Pattern 3: 1 + 3 x 4 = 13
Formula:
Number of squares = 1 + Pattern number x 4
Number of squares needed to form Pattern 17
= 1 + 17 x 4
= 69
(b)
1 + Pattern number x 4 = 25
Pattern number x 4 = 25 - 1 = 24
Pattern number = 24 ÷ 4 = 6
Pattern number = Number of triangles
Pattern number 6 = 6 triangles
Answer(s): (a) 69; (b) 6