हिंदी

If one of the angles of a triangle is 110°, then the angle between the bisectors of the other two angles is ______. - Mathematics

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प्रश्न

If one of the angles of a triangle is 110°, then the angle between the bisectors of the other two angles is ______.

विकल्प

  • 70°

  • 110°

  • 35°

  • 145°

MCQ
रिक्त स्थान भरें

उत्तर

If one of the angles of a triangle is 110°, then the angle between the bisectors of the other two angles is 145°.

Explanation:

In ΔABC, ∠A = 110°  .....[Given]


We know that, ∠A + ∠B + ∠C = 180°  ......[Angle sum property of a triangle]

⇒ ∠B + ∠C = 180° – ∠A

⇒ ∠B + ∠C = 180° – 110°

⇒ ∠B + ∠C = 70°  ......(i)

⇒ `1/2 ∠B + 1/2 ∠C = 70/2` = 35°  ......[∵ Equation (i) is divided by 2]

⇒ `1/2 (∠B + ∠C)` = 35°

Now, In ΔBOC,

∠BOC + ∠OBC + ∠OCB = 180°  [Angle sum property of a triangle]  ......(ii)

⇒ `∠BOC + 1/2 (∠B + ∠C)` = 180°  ......[∵ OB and OC are the bisectors of ∠B and ∠C, then ∠OBC = `1/2`∠B and ∠OCB = `1/2`∠C]

⇒ ∠BOC + 35° = 180°

⇒ ∠BOC = 180° – 35°

⇒ ∠BOC = 145°

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  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 6: Triangles - Exercise [पृष्ठ १६३]

APPEARS IN

एनसीईआरटी एक्झांप्लर Mathematics [English] Class 7
अध्याय 6 Triangles
Exercise | Q 27. | पृष्ठ १६३

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