Choose the statement that is true. a. if two polygons are congruent, then they are similar. b. if two quadrilaterals are rhombi, then they are similar. c. if two hexagons are equiangular, then they are similar. d. if two triangles are isosceles, then they are similar.

The correct answer is:
A) If two polygons are congruent, then they are similar.

Explanation:
If two polygons are congruent, this means that all of the angle measures are the same and the side lengths are the same as well.

Similar figures have equal angle measures while the ratio of corresponding sides is the same; this is also true of congruent figures.
 
Therefore congruent figures are also similar. While we usually think of equi-angular figures as "regular" figures (the side lengths being equal), that is not always the case. It is possible to have two equi-angular hexagons with different side lengths and different ratios of the corresponding sides; this would not be similar.

Option: A is the correct answer.

A.   If two polygons are congruent, then they are similar.

Step-by-step explanation:

Two polygons are said to be congruent if:

They have the same number of the sides.All the corresponding sides are of the same length.All the corresponding interior angles are of equal measure.

Two polygons are said to be similar if they have the congruent angles and also the corresponding sides are proportional.

Hence, as they will be congruent the property of similarity trivially holds and hence, the polygons that are congruent are similar as well.

          Hence, option: A is correct.