Which pairs of rectangles are similar polygons? select each correct answer.

By similarities, the question means that the pairs whose corresponding sides have the same ratio. That is given two figures say rectangles A and B, then:
length A/Length B =Width A/Width B
To know which pairs are similar, we plug in their values in the above formula:
Pair 1
169/1.3=130
49/0.7=70
130 ≠70
therefore the first pair is not similar

Pair 2
18.55/5.3=3.5
10.5/3.5=3
Pair 2 is not similar

Pair 3
120/24=5
60/12=5
this implies that pair 3 is similar
 Pair 4
189/2.1=90
81/0.9=90

this implies that pair 4 is similar