Each of the figure is made up of 3-cm sticks. The table shows the total length of sticks used for each figure and the perimeter of each figure.
- Complete the table for Figure 8 (i).
- Complete the table for Figure 8 (ii).
- Which figure number will have a perimeter of 630 cm?
(a)
Pattern of the total length of sticks
Figure 1: (1 x 11 + 1) x 3 = 36 cm
Figure 2: (2 x 11 + 1) x 3 = 69 cm
Figure 3: (3 x 11 + 1) x 3 = 102 cm
Formula:
Total length of sticks = (Figure number x 11 + 1) x 3
Total length of sticks for Figure 8
= (8 x 11 + 1) x 3
= 89 x 3
= 267 cm
(b)
Pattern of the perimeter
Figure 1: (1 x 4 + 2) x 3 = 18 cm
Figure 2: (2 x 4 + 2) x 3 = 30 cm
Figure 3: (3 x 4 + 2) x 3 = 42 cm
Formula:
Perimeter of Figure= (Figure number x 4 + 2) x 3
Perimeter of Figure 8
= (8 x 4 + 2) x 3
= 34 x 3
= 102 cm
(c)
(Figure number x 4 + 2) x 3 = 630
Figure number x 4 + 2 = 630 ÷ 3
Figure number x 4 + 2 = 210
Figure number x 4 = 210 - 2
Figure number x 4 = 208
Figure number = 208 ÷ 4
Figure number = 52
Answer(s): (a) 267; (b) 102; (c) 52