The figure shows a pattern formed using some ice-cream sticks.
- How many ice-cream sticks are used to form 89 squares?
- How many squares can be formed using 91 ice-cream sticks?
(a)
Pattern for the number of ice-cream sticks
1 square: 1 x 3 + 1 = 4
2 squares: 2 x 3 + 1 = 7
3 squares: 3 x 3 + 1 = 10
Formula
Number of ice-cream sticks = Number of squares x 3 + 1
Number of ice-cream sticks for 89 squares
= 89 x 3 + 1
= 268
(b)
Number of squares x 3 + 1 = 91
Number of squares x 3 = 91 - 1
Number of squares = 90 ÷ 3
Number of squares = 30
Answer(s): (a) 268; (b) 30