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I is the incentre of Delta ABC, angle AB...

I is the incentre of `Delta ABC, angle ABC=60^(@)` and `angle ACB=50^(@)`. Then find `angle BIC`.

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To find the angle \( \angle BIC \) in triangle \( ABC \) where \( I \) is the incenter, and given that \( \angle ABC = 60^\circ \) and \( \angle ACB = 50^\circ \), we can follow these steps: ### Step-by-Step Solution: 1. **Determine \( \angle BAC \)**: - We know that the sum of angles in a triangle is \( 180^\circ \). - Therefore, we can find \( \angle BAC \) as follows: \[ \angle BAC = 180^\circ - \angle ABC - \angle ACB \] Substituting the known values: \[ \angle BAC = 180^\circ - 60^\circ - 50^\circ = 70^\circ \] 2. **Find the angles at the incenter \( I \)**: - The angles \( \angle IBC \) and \( \angle ICB \) are half of \( \angle ABC \) and \( \angle ACB \) respectively because \( I \) is the incenter. - Therefore: \[ \angle IBC = \frac{1}{2} \times \angle ABC = \frac{1}{2} \times 60^\circ = 30^\circ \] \[ \angle ICB = \frac{1}{2} \times \angle ACB = \frac{1}{2} \times 50^\circ = 25^\circ \] 3. **Use the angle sum property in triangle \( BIC \)**: - In triangle \( BIC \), the sum of angles is \( 180^\circ \): \[ \angle IBC + \angle BIC + \angle ICB = 180^\circ \] - Substituting the known values: \[ 30^\circ + \angle BIC + 25^\circ = 180^\circ \] 4. **Solve for \( \angle BIC \)**: - Combine the known angles: \[ 55^\circ + \angle BIC = 180^\circ \] - Rearranging gives: \[ \angle BIC = 180^\circ - 55^\circ = 125^\circ \] ### Final Answer: \[ \angle BIC = 125^\circ \]
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ADVANCED MATHS BY ABHINAY MATHS ENGLISH-GEOMETRY TRIANGLES-QUESTIONS
  1. In a Delta ABC, I is incenter, angle BIC=116^(@) find angle A.

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  2. O is the incentre of Delta ABC and angle A=30^(@), then find angle BOC...

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  3. I is the incentre of Delta ABC, angle ABC=60^(@) and angle ACB=50^(@)....

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  4. Let O be the in-centre of a triangle ABC and D be a point on the side ...

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  5. In a Delta ABC, angle bisector of angle A, angle B & angle C cuts circ...

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  6. In a DeltaABC, AD is angle bisector , AB=7 cm , AC=8 cm, BC=6cm, If I ...

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  7. If the circumradius of a triangle is 7 cm and inradius is 3 cm . Find ...

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  8. I and O are incentre and circumcentre of a Delta ABC. AI is produced a...

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  9. In a Delta ABC, angleBOC=130^(@), if O is orthocentre . Find angle A.

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  10. If the lengths of the sides of a triangle are in the ratio 4:5:6 and t...

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  11. In a Delta ABC, AB=10 cm, BC=12 and AC=18 cm. Find the length of small...

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  12. O is the Ortho centre of Delta ABC then A will be Orthocentre

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  13. D is a point on side BC of a Triangle ABC such that AD bot BC and E...

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  14. O and C are respectively orthocentre and circumcentre of a Delta PQR. ...

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  15. In a triangle the distance b/w centroid and orthocentre is 18 cm . Fi...

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  16. In Delta XYZ, I is incentre , O is orthocentre & C is circumcentre . a...

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  17. In a triangle ABC, there are three point P, Q & R on side BC, such tha...

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  18. In a Delta ABC, angle bisector of exterior angle B & angle C meets at ...

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  19. Find the ex-radius of a ex-circle which touches side BC. AB=13 cm, ...

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  20. In a triangle aBC , angleB=2angleC.AD and BE bisectors of angleBACanda...

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