Each of the figures is made up of 1-cm ice-cream sticks.
The table shows the number of ice-cream sticks used to make the figures and their perimeters.
- Find the number of ice-cream sticks in Figure 19.
- What is the perimeter of Figure 69?
- Which figure requires a total number of 1447 ice-cream sticks?
(a)
Pattern for the number of ice-cream sticks
Figure 1: 1 x 8 + 7 = 15
Figure 2: 2 x 8 + 7 = 23
Figure 3: 3 x 8 + 7 = 31
Formula:
Number of ice-cream sticks = Pattern number x 8 + 7
Number of ice-cream sticks in Figure 19
= 19 x 8 + 7
= 159
(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 69
= 69 x 2 + 7
= 145
(c)
Figure number x 8 + 7 = 1447
Figure number x 8 = 1447 - 7 = 1440
Figure number = 1440 ÷ 8 = 180
Answer(s): (a) 159; (b) 145; (c) 180