Look at the pattern.
- What is the perimeter of Figure 9?
- What is the area of Figure 12?
- What is the perimeter of Figure 12?
(a)
Figure perimeter:
Figure 1 = 10 x 2 = 20 cm
Figure 2 = 10 x 3 = 30 cm
Figure 3 = 10 x 4 = 40 cm
Figure 4 = 10 x 5 = 50 cm
Formula:
Perimeter = 10 x (Figure Number + 1)
Perimeter of Figure 9
= 10 x (9 + 1)
= 10 x 10
= 100 cm
(b)
Figure Area:
Figure 1 = 1 x 25 = 25 cm
2 Figure 2 = 2 x 25 = 50 cm
2 Figure 3 = 3 x 25 = 75 cm
2 Figure 4 = 4 x 25 = 100 cm
2 Area of Figure 12
= 12 x 25
= 300 cm
2 (c)
Perimeter of Figure 12
= 10 x (12 + 1)
= 10 x 13
= 130 cm
Answer(s): (a) 100 cm; (b) 300 cm
2; (c) 130 cm