The figure shows a pattern formed using some matchsticks.
- How many matchsticks are used to form 71 squares?
- How many squares can be formed using 355 matchsticks?
(a)
Pattern for the number of matchsticks
1 square: 1 x 3 + 1 = 4
2 squares: 2 x 3 + 1 = 7
3 squares: 3 x 3 + 1 = 10
Formula
Number of matchsticks = Number of squares x 3 + 1
Number of matchsticks for 71 squares
= 71 x 3 + 1
= 214
(b)
Number of squares x 3 + 1 = 355
Number of squares x 3 = 355 - 1
Number of squares = 354 ÷ 3
Number of squares = 118
Answer(s): (a) 214; (b) 118