Answer: Equilateral triangles.
Explanation: We know that in similar polygons, its all the corresponding angles are congruent. Only the set of equilateral triangles contains members that are always similar( by AAA similarity criteria) to one another as the measure of all the angles of equilateral triangle is fixed i.e. 60°.
Rest other do not have fixed measure for angles in it.
Answer:
It is (D)

Step-by-step explanation:
I hope that is useful for you
Answer:
See explanation
Step-by-step explanation:
Given two expressions:

and

a. When 
then

and

b. When 
then

and

c. Since the value of both expressions at s = 12 are different, the expressions are not equivalent.
This is just me typing so that it’s 20 letters long