In , is the mid-point of side . A student attempted to prove that is congruent to…

MATHEMATICS · Multi-part · CBSE · Mathematics · Triangles · Triangles

Problem

In △ABC\triangle ABC, DD is the mid-point of side BCBC. A student attempted to prove that △ABD\triangle ABD is congruent to △ACD\triangle ACD using the following steps: “AB=ACAB = AC (given), BD=CDBD = CD (since DD is the mid-point of BCBC), ∠BAD=∠CAD\angle BAD = \angle CAD (common) ⇒ △ABD≅△ACD\triangle ABD \cong \triangle ACD by SAS.” (i) Point out the specific error in the student's reasoning. (ii) Write a correct proof to establish the congruence of △ABD\triangle ABD and △ACD\triangle ACD, clearly stating the criterion applied. (iii) After proving congruence, state any two pairs of corresponding parts of the triangles that are equal.

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