The figures are formed using sticks and dots. The table shows the number of sticks and dots used for each figure.
- Find (i).
- Find (ii).
- Which figure would need a total of 98 sticks and dots?
(a)
Pattern for the number of sticks used
Figure 1: 1 x 4 - 2 = 2
Figure 2: 2 x 4 - 2 = 6
Figure 3: 3 x 4 - 2 = 10
Formula
Number of sticks = Figure number x 4 - 2
Number of sticks used for Figure 8
= 8 x 4 - 2
= 32 - 2
= 30
(b)
Pattern for the total number of sticks and dots
Figure 1: 1 x 5 - 2 = 3
Figure 2: 2 x 5 - 2 = 8
Figure 3: 3 x 5 - 2 = 13
Formula
Total number of sticks and dots = Figure number x 5 - 2
Total number of sticks and dots for Figure 8
= 8 x 5 - 2
= 40 - 2
= 38
(c)
Total number of sticks and dots = Figure number x 5 - 2
Figure number x 5 - 2 = 98
Figure number x 5 = 98 + 2
Figure number x 5 = 100
Figure number = 100 ÷ 5 = 20
Answer(s): (a) 30; (b) 38; (c) 20