1. a) 2 : x = 1 : 100
1 : 0.5x = 1 : 100
0.5x = 100
x = 200
b) x : 2.25 = 1 : 12
2.25 = 12x
x = 0.1875
c) 1.6 : 6.4 = 1 : x
1 : 4 = 1 : x
x = 4
d) 1.5 : x = 1 : 500
x = 500 x 1.5
x = 750
2. Since 1 cm = 2 inches and the height given is 4 cm, the bottle's height is (2 x 4) inches, that is, 8 inches.
3. Since 1 cm = 0.8 m, the length of the car is (5 x 0.8) m = 4 m.
I hope this helps! If you have any questions, feel free to ask.