Question

two triangles are congruent and the corresponding if and only if the corresponding are congruent. remember that angles are always congruent. markings for these angles can be added to a diagram of triangles. the property states that any object (angle, line, etc.) is congruent to itself. these markings can be added to a diagram of triangles if the two figures share an or.

Explanation:

1. Two triangles are congruent if and only if the corresponding sides and corresponding angles are congruent. This is the fundamental definition of triangle - congruence.
2. The reflexive property states that any object (such as an angle or a line - segment) is congruent to itself. For example, in a triangle, an angle within the triangle can be considered congruent to itself when comparing parts for congruence proofs.
3. Vertical angles are always congruent. When two lines intersect, the pairs of opposite angles formed are called vertical angles and they have equal measures. Markings for these congruent angles can be added to a diagram of triangles when they are part of the congruence - related elements. Also, if two figures share a common side or angle, markings can be added to indicate this in the context of proving triangle congruence.

Answer:

1. sides; angles
2. reflexive
3. vertical