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Today a new place for jogging xDganga dhaar me |
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Answer» Answer: Given: Two parallel lines AB and CD and a TRANSVERSAL EF intersect them at G and H respectively. GM, HM, GL and HL are the bisectors of the two pairs of interior angles. To Prove: GMHL is a rectangle. Proof: ∵AB∥CD ∴∠AGH=∠DHG (Alternate interior angles) ⇒21∠AGH=21∠DHG ⇒∠1=∠2 (GM & HL are bisectors of ∠AGH and ∠DHG respectively) ⇒GM∥HL (∠1 and ∠2 from a pair of alternate interior angles and are equal) SIMILARLY, GL∥MH So, GMHL is a parallelogram. ∵AB∥CD ∴∠BGH+∠DHG=180o (Sum of interior angles on the same side of the transversal =180o) ⇒21∠BGH+21∠DHG=90o ⇒∠3+∠2=90o .....(3) (GL & HL are bisectors of ∠BGH and ∠DHG respectively). In ΔGLH,∠2+∠3+∠L=180o ⇒90o+∠L=180o Using (3) ⇒∠L=180o−90o ⇒∠L=90o Thus, in parallelogram GMHL, ∠L=90o Hence, GMHL is a rectangle. |
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