If two right triangles each have a 30° angle, then the triangles must be
a equilateral
b. similar
C. obtuse
D. congruency

b. Similar

Step-by-step explanation:

Although angles are congruent the triangles are not as sides need to be the same too.  Both shapes have 90 degree and 30 degree and add up to 180 degree in each triangle. Therefore each shapes angles are congruent but we dont know there size or scale, so they are similar. if they are the same (shape and size)- in other words, if the lengths of the sides and the angles are the same. So they are similar.

Because the angles are congruent and sizes are not shown they must be similar.

They cannot be obtuse as no angle is larger than 90 degrees and to be obtuse it would have to be larger than 90 deg and lower than 180 deg.

They cannot be equilateral as that means it couldn't be 30 degree and a right angle as equilateral means same angle sizes within 'one' triangle or for every or each triangle; as we know all triangles that are equilateral are 60, 60, 60 degrees to add up to 180 degree and cannot be an equilateral for this reason too as we have right angle triangles and equilateral are not right angles due to being 60 degree angle measures.

They are not fully congruent as we do not know there side measures so they have to be similar.

B

Step-by-step explanation:

Two triangles are similar when they share at least two angles and the only difference is size.