CONGRUENCE D1

Prove that ∆ABC and ∆DCG are congruent in the figure below: 

Solution

Given: figure ABCGD.

Required to prove: ∆ABC and ∆DCG are congruent

Proof: 

AC = CD    (given)

<BAC = <CDG = 50⁰ (given)

<ACB = <DCG (opposite angles)

Hence ∆ACB ≡ ∆DCG by AAS rule (proved)