Answer:
All right angles are congruent.
Step-by-step explanation:
Two figures are said to be congruent if they overlap each other.
Acute angles whose measure is less than
.
Obtuse angles are angles whose measure lie between
and 
An angle equals to
is a straight angle.
An angle whose measure is between
and
is a reflex angle.
An angle equal to
is a complete angle.
We know that two angles are congruent if they have same measure.
Two right angles are always congruent as they are always equal to 
So,
≅
as they are right angles and all right angles are congruent.