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L and mare two parallel lines intersected by anotherpair of parallel Linee P Рshow that ABC SCOA |
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Answer» Answer: Given : l∥m TRANSVERSAL p intersects l & m at A & C RESPECTIVELY. Bisector of ∠ PAC & ∠ QCA meet at B. And, bisector of ∠ SAC & ∠ RCA meet at D. To prove : ABCD is a rectangle. Proof : We know that a rectangle is a parallelogram with one ANGLE 90 o . For l∥m and transversal p ∠PAC=∠ACR So, 2 1
∠PAC= 2 1
∠ACR So, ∠BAC=∠ACD For LINES AB and DC with AC as transversal ∠BAC & ∠ACD are alternate angles, and they are equal. So, AB∥DC. Similarly, for lines BC & AD, with AC as transversal ∠BAC & ∠ACD are alternate angles, and they are equal. So, BC∥AD. Now, In ABCD, AB∥DC & BC∥AD As both pair of opposite sides are parallel, ABCD is a parallelogram. Also, for line l, ∠PAC+∠CAS=180 o
2 1
∠PAC+ 2 1
∠CAS=90 o
∠BAC+∠CAD=90 o
∠BAD=90 o . So, ABCD is a parallelogram in which one angle is 90 o . Hence, ABCD is a rectangle. solution Expand-image |
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