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

1. Find the number of chopsticks in Figure 8.
2. What is the perimeter of Figure 158?
3. Which figure requires a total number of 1591 chopsticks?

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

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

Number of chopsticks in Figure 8
= 8 x 8 + 7
= 71

(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 158
= 158 x 2 + 7
= 323

(c)
Figure number x 8 + 7 = 1591
Figure number x 8 = 1591 - 7 = 1584
Figure number = 1584 ÷ 8 = 198

Answer(s): (a) 71; (b) 323; (c) 198