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

1. Find the number of wooden rods in Figure 11.
2. What is the perimeter of Figure 105?
3. Which figure requires a total number of 1799 wooden rods?

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

Formula:
Number of wooden rods = Pattern number x 8 + 7

Number of wooden rods in Figure 11
= 11 x 8 + 7
= 95

(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 105
= 105 x 2 + 7
= 217

(c)
Figure number x 8 + 7 = 1799
Figure number x 8 = 1799 - 7 = 1792
Figure number = 1792 ÷ 8 = 224

Answer(s): (a) 95; (b) 217; (c) 224