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In a Delta ABC, angle bisector of angle ...

In a `Delta ABC`, angle bisector of `angle A, angle B & angle C` cuts circumcircle at P, Q , R respectively . If `angle CRQ=46^(@)& angle A=50^(@)`, then find `angle BQR`.

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To solve the problem, we need to find the angle \( \angle BQR \) in triangle \( ABC \) given that \( \angle CRQ = 46^\circ \) and \( \angle A = 50^\circ \). ### Step-by-Step Solution: 1. **Identify the Angles in Triangle ABC**: - We know \( \angle A = 50^\circ \). - Let \( \angle B = b \) and \( \angle C = c \). - The sum of angles in triangle \( ABC \) is \( 180^\circ \): \[ \angle A + \angle B + \angle C = 180^\circ \implies 50^\circ + b + c = 180^\circ \implies b + c = 130^\circ \] 2. **Use the Angle Bisector Theorem**: - The angle bisector of \( \angle C \) intersects the circumcircle at point \( R \). - According to the angle bisector theorem, the angle \( \angle QNR \) (where \( N \) is the intersection of the angle bisectors) can be expressed as: \[ \angle QNR = 90^\circ + \frac{\angle A}{2} = 90^\circ + \frac{50^\circ}{2} = 90^\circ + 25^\circ = 115^\circ \] 3. **Calculate \( \angle BQR \)**: - In triangle \( QNR \), we know: \[ \angle CRQ = 46^\circ \quad \text{and} \quad \angle QNR = 115^\circ \] - We can find \( \angle BQR \) using the fact that the sum of angles in triangle \( QNR \) is \( 180^\circ \): \[ \angle BQR + \angle CRQ + \angle QNR = 180^\circ \] \[ \angle BQR + 46^\circ + 115^\circ = 180^\circ \] \[ \angle BQR + 161^\circ = 180^\circ \] \[ \angle BQR = 180^\circ - 161^\circ = 19^\circ \] ### Final Answer: \[ \angle BQR = 19^\circ \]
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ADVANCED MATHS BY ABHINAY MATHS ENGLISH-GEOMETRY TRIANGLES-QUESTIONS
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