Some beads were used to create the figures .
- How many beads were used to create Figure 9?
- A pattern is formed with 689 beads. Which figure would it be?
(a)
Pattern for the number of beads
Figure 1: (1 - 1) x 4 + 1 = 1
Figure 2: (2 - 1) x 4 + 1 = 5
Figure 3: (3 - 1) x 4 + 1 = 9
Formula
Number of beads = (Figure number - 1) x 4 + 1
Number of beads for Figure 9
= (9 - 1) x 4 + 1
= 33
(b)
Figure number with 689 beads
= (689 - 1) ÷ 4 + 1
= 688 ÷ 4 + 1
= 173
Answer(s): (a) 33; (b) 173
