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.
- Find the number of chopsticks in Figure 12.
- What is the perimeter of Figure 147?
- Which figure requires a total number of 1695 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 12
= 12 x 8 + 7
= 103
(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 147
= 147 x 2 + 7
= 301
(c)
Figure number x 8 + 7 = 1695
Figure number x 8 = 1695 - 7 = 1688
Figure number = 1688 ÷ 8 = 211
Answer(s): (a) 103; (b) 301; (c) 211