Each of the figures is made up of 1-cm matchsticks.
The table shows the number of matchsticks used to make the figures and their perimeters.

1. Find the number of matchsticks in Figure 17.
2. What is the perimeter of Figure 132?
3. Which figure requires a total number of 3431 matchsticks?

(a)
Pattern for the number of matchsticks
Figure 1: 1 x 8 + 7 = 15
Figure 2: 2 x 8 + 7 = 23
Figure 3: 3 x 8 + 7 = 31

Formula:
Number of matchsticks = Pattern number x 8 + 7

Number of matchsticks in Figure 17
= 17 x 8 + 7
= 143

(b)
Pattern for the perimeter of the figure
Figure 1 = 1 x 2 + 7 = 9
Figure 2 = 2 x 2 + 7 = 11
Figure 3 = 3 x 2 + 7 = 13

Formula:
Perimeter of the figure = Pattern number x 2 + 7

Perimeter of figure 132
= 132 x 2 + 7
= 271

(c)
Figure number x 8 + 7 = 3431
Figure number x 8 = 3431 - 7 = 3424
Figure number = 3424 ÷ 8 = 428

Answer(s): (a) 143; (b) 271; (c) 428