17. The following figures are made up of 2-cm squares.
a) What is the perimeter of Figure 3?
b) How many squares are there in Figure 6?
c) Which figure has an area of 220 cm2?
By moving all sides out, we get a big square.
3 x 4 = 12
12 x 2 = 24 cm
a) The perimeter of Figure 3 is 24 cm.
1
1 + 2
1 + 2 + 3
..
1 + 2 + 3 + 4 + 5 + 6 = 21 squares
b) There are 21 squares in Figure 6.
2 x 2 = 4
220 ÷ 4 = 55 squares
21 + 7 = 28
28 + 8 = 36
36 + 9 = 45
45 + 10 = 55 -- > Figure 10
c) Figure 10 has an area of 220 cm2.
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