Answer:
x = 6 cm
Explanation:
The two shapes are similar. That means one figure is exactly a multiple of the other figure
We can see that the ration of the length of the bigger rectangle to the length of the smaller rectangle is 15/9 = 5/3
Therefore the ratio of the width of the bigger rectangle to the width of the smaller rectangle must also be 5/3
Given width of big rectangle = 10 and that of small rectangle is x
We get
10/x = 5/3
Multiply by x both sides:
x × 10/x = x × 5/3
10 = 5x/3
Multiply by 3 both sides
30 = 5x
5x = 30
Dividing by 5 both sides
5x/x = 30/5
x = 6 cm