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 19.
2. What is the perimeter of Figure 75?
3. Which figure requires a total number of 1479 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 19
= 19 x 8 + 7
= 159

(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 75
= 75 x 2 + 7
= 157

(c)
Figure number x 8 + 7 = 1479
Figure number x 8 = 1479 - 7 = 1472
Figure number = 1472 ÷ 8 = 184

Answer(s): (a) 159; (b) 157; (c) 184