Its an indirect proof, so 3 steps :- 1) you start with the opposite of wat u need to prove 2) arrive at a contradiction 3) concludeReport · 29/6/2015261 since you wanto prove 'diagonals of a parallelogram bisect each other', you start wid the opposite of above statement, like below :- step1 : Since we want to prove 'diagonals of a parallelogram bisect each other', lets start by assuming the opposite, that the diagonals of parallelogram dont bisect each other.Report · 29/6/2015261
Since, we assumed that the diagonals dont bisect each other, OC≠OA OD≠OBReport · 29/6/2015261 Since, OC≠OA, △OAD is not congruent to △OCBReport · 29/6/2015261
∠AOD≅∠BOC as they are vertical angles, ∠OAD≅∠OCB they are alternate interior angles AD≅BC, by definition of parallelogram so, by AAS, △OAD is congruent to △OCBReport · 29/6/2015261 But, thats a contradiction as we have previously established that those triangles are congruentReport · 29/6/2015261 step3 : since we arrived at a contradiction, our assumption is wrong. so, the opposite of our assumption must be correct. so diagonals of parallelogram bisect each other.
