A. First of all I labelled the long side b and the short side a. I already know that one 'I' shape has a height of 13 cm, there are two full 'I' shapes in the bigger shape and I know that the bigger shape has a height of 33cm. This means that because there are two I shapes in the bigger shape and they are each 13cm side b must be 7cm. 13-7=6/2=3 so b=7 and a=3
P=2a+2b
P=(2x3)+(2x7)
P=6+14
P=20cm
B. To help solve B I used a and b. First I labelled the long side b and the short side a. To find the perimeter of the small rectangles all we really need to do is find what side b is equal to, we only need to find b because from looking at the diagram we know that b=3a. We can find out what the perimeter is from the area, the area is 60 cm squared and the formula to find this is bx(2a+b). Now we can use trial and error to find out what a and b are equal to at first I tried b=6 and a=3 but that gave me 72 which is 12 more than I need. After that I decided to try b=6 and a=2.
6x(2x2+6)
6x(4+6)
6x10=60
This means the perimeter of a small rectangle=
P=2a+2b
P=(6x2)+(2x2)
P=12+4
Perimeter of each small rectangle=16cm
C.Like with be to help me solve the question I'm going to use a and b to help me solve the problem. I labelled the long side b and the short side a, we know from looking at this that b=4a and we also know that the area is 600mm squared. I used the multiples to help me find the lengths this time, I used b=60mm and a=20mm I also used the formula bx(2a+b)
60mmx(2x20+60)
60x(40+60)
60x100=600
This means the perimeter of the small rectangle=
P=2a+2b
P=(2x20)+(2x60)
P=40+120
Perimeter of each individual rectangle=160mm
D.The whole rectangle has an area of 180cm squared and there are 9 rectangles. If you divide 180 by 9 you get 20cm squared which is the area of each individual rectangle. I also used a and b again and a is the short side side and b is the long side. I used multiples again so I tried a=4 and b=5
20=axb
20=4x5
This means perimeter=
P=2a+2b
P=(4x2)+(2x5)
P=8+10
Perimeter of each individual rectangle=18