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In the figure , ABCD is a parallelogram. P, Q , R , S are the midpoint of the sides of the parallelogram . Then prove that PQ = RS and QR = PS |
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Answer» Answer: Step-by-step explanation: Given : - ABCD is a parallelogram P , Q , R & S are the mid points of the sides AB , BC , CD , DA Required to PROVE : - PQ = RS QR = PS Theorem used : - Mid point theorem This states that ; The line segments joining the midpoints of the two sides of the triangle is parallel to the third side and also half of the third side . Solution : -ABCD is a parallelogram P , Q , R & S are the mid points of the sides AB , BC , CD , DA Here, AC is a DIAGONAL . Consider ∆ ABC & ∆ ADC In ∆ ABC & ∆ ADC . => AC = AC ( side ) [ Reason : Common side ] => AB = CD ( side ) [ Reason : In a parallelogram, opposite sides are equal ] => AD = BC ( side ) [ Reason : In a parallelogram , opposite angles are equal ] By using S.S.S. Congruency rule ∆ ABC ∆ADC However, Similarly, if you want to write easily you can write that in a parallelogram a diagonal divides it into 2 Congruency triangles . so ∆ ABC ∆ADC This implies ; PQ = ½ AC RS = ½ AC [ Reason : Mid point theorem ] SINCE, RHS part is equal . Let's equate the LHS part . Hence, PQ = RS Similarly, Construction : -Draw the diagonal BD in the ||gm PQRS . Consider ∆ BCD & ∆ BAD In ∆ BCD & ∆ BAD => BD = BD ( side ) [ Reason : Common side ] => BC = AD ( side ) [ Reason : Opposite sides are equal ] => CD = AB ( side ) [ Reason : Opposite sides are equal ] By using S.S.S. Congruency rule ; ∆ BCD ∆BAD This implies ; QR = ½ BD QR = ½ BD PS = ½ BD [ Reason : Mid point theorem ] Since, RHS part is equal . Let's equate the LHS part Hence, QR = PS Hence Proved Hope my answer helps youMark me as brainliest |
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