Rods are used to make the figures as shown.
- How many rods are used to make Figure 15?
- Which figure requires the use of 190 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 15
= 15 x 6 - 2
= 90 - 2
= 88
(b)
Figure Number x 6 - 2 = 190
Figure Number x 6 = 190 + 2
Figure Number x 6 = 192
Figure Number = 192 ÷ 6
Figure Number = 32
Figure Number that requires the use of 190 rods = 32
Answer(s): (a) 88; (b) 32