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 10.
- What is the perimeter of Figure 140?
- Which figure requires a total number of 3639 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 10
= 10 x 8 + 7
= 87
(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 140
= 140 x 2 + 7
= 287
(c)
Figure number x 8 + 7 = 3639
Figure number x 8 = 3639 - 7 = 3632
Figure number = 3632 ÷ 8 = 454
Answer(s): (a) 87; (b) 287; (c) 454