Each of the figure is made up of 5-cm sticks. The table shows the total length of sticks used for each figure and the perimeter of each figure.

1. Complete the table for Figure 5 (i).
2. Complete the table for Figure 5 (ii).
3. Which figure number will have a perimeter of 1870 cm?

(a)
Pattern of the total length of sticks
Figure 1: (1 x 11 + 1) x 5 = 60 cm
Figure 2: (2 x 11 + 1) x 5 = 115 cm
Figure 3: (3 x 11 + 1) x 5 = 170 cm

Formula:
Total length of sticks = (Figure number x 11 + 1) x 5

Total length of sticks for Figure 5
= (5 x 11 + 1) x 5
= 56 x 5
= 280 cm

(b)
Pattern of the perimeter
Figure 1: (1 x 4 + 2) x 5 = 30 cm
Figure 2: (2 x 4 + 2) x 5 = 50 cm
Figure 3: (3 x 4 + 2) x 5 = 70 cm

Formula:
Perimeter of Figure= (Figure number x 4 + 2) x 5

Perimeter of Figure 5
= (5 x 4 + 2) x 5
= 22 x 5
= 110 cm

(c)
(Figure number x 4 + 2) x 5 = 1870
Figure number x 4 + 2 = 1870 ÷ 5
Figure number x 4 + 2 = 374
Figure number x 4 = 374 - 2
Figure number x 4 = 372
Figure number = 372 ÷ 4
Figure number = 93

Answer(s): (a) 280; (b) 110; (c) 93