Rods are used to make the figures as shown.
- How many rods are used to make Figure 13?
- Which figure requires the use of 160 rods?
(a)
Pattern for the number of rods
Figure 1: 1 x 6 - 2 = 4
Figure 2: 2 x 6 - 2 = 10
Figure 3: 3 x 6 - 2 = 16
Figure 4: 4 x 6 - 2 = 22
Formula:
Number of rods used = Figure Number x 6 - 2
Number of rods used to make Figure 13
= 13 x 6 - 2
= 78 - 2
= 76
(b)
Figure Number x 6 - 2 = 160
Figure Number x 6 = 160 + 2
Figure Number x 6 = 162
Figure Number = 162 ÷ 6
Figure Number = 27
Figure Number that requires the use of 160 rods = 27
Answer(s): (a) 76; (b) 27
