हिंदी

In triangle ABC, the medians BP and CQ are produced up to points M and N respectively such that BP = PM and CQ = QN. Prove that: M, A, and N are collinear. A is the mid-point of MN. - Mathematics

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प्रश्न

In triangle ABC, the medians BP and CQ are produced up to points M and N respectively such that BP = PM and CQ = QN. Prove that:

  1. M, A, and N are collinear.
  2. A is the mid-point of MN.
योग
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उत्तर

The figure is shown below

(i) In ΔAQN & ΔBQC 

AQ = QB (Given)

∠AQN = ∠BQC                       

QN = QC 

∴ ΔAQN ≅ ΔBQC                     ...[ by SAS  ] 

∴ ∠QAN = ∠QBC                   ...(1)

And BC = AN ……(2)

Similarly, ΔAPM ≅ ΔCPB           .....[by SAS] 

∠PAM = ∠PCB                      ...(3)  [by CPTC]        

And BC = AM                          ….( 4 )

Now In ΔABC,

∠ABC + ∠ACB + ∠BAC = 180°

∠QAN + ∠PAM + ∠BAC = 180°   ...[ (1), (2) we get ]

Therefore M, A, N are collinear.

(ii) From (3) and (4) MA = NA

Hence A is the midpoint of MN.

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  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 12: Mid-point and Its Converse [ Including Intercept Theorem] - Exercise 12 (B) [पृष्ठ १५४]

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सेलिना Concise Mathematics [English] Class 9 ICSE
अध्याय 12 Mid-point and Its Converse [ Including Intercept Theorem]
Exercise 12 (B) | Q 4 | पृष्ठ १५४

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