The missing reason in the proof is SAS -side angle side postulate
<h3>How to find the missing proof in congruent triangles</h3>
A triangle is said to be congruent if the sides and angles are similar. The notations are explained as follows:
Using two triangles say AA and BB as instance
SAS : side angle side: this means that the two sides of triangle AA is equal to the two sides of triangle BB. For the angle it should be the angle between the two equal sides, that is to say the angle where the two sides intersect.
This is the correct option for the question asked given that
line AB ≅ AC ( first statement ) = Side
< B ≅ < D ( fourth statement ) = Angle
line BD ≅ CD ( third statement ) = Side
This represents the side angle side postulate which is one of the postulates required to prove that triangles are equal
Read more on angle postulate here: brainly.com/question/3999145
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