Answer: SAS property.
Step-by-step explanation: The problem gives you the value of two sides and an angle that these two sides share. Based on these values, you can use the SAS angle property to prove they are similar. The SAS property, as its name states, is a property that proves that two triangles are similar if two of their sides have a common ratio (in this case, their common ratio is 1:2) and one angle these two sides share is congruent to the other (in this case, shared angle A and D are congruent).
