Math, asked by nihaal77, 1 year ago

In the given figure centre point O ,angle PQR=100° find angle OPR

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Answered by Anonymous
68

Hello mate =_=

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Solution:

P, Q and R are the points on a circle with centre O where ∠PQR=100°

Construction: S is a point on the major arc PR. Join P and S, R and S to form a cyclic quadrilateral.

 

∠PQR+∠PSR=180°

(Sum of opposite angles of a cyclic quadrilateral is equal to 180°)

⇒100°+∠PSR=180°

⇒∠PSR=180°−100°=80°

Also, ∠POR=2∠PSR

(Angle subtended by an arc at the centre is double the angle subtended by it at the circumference of the circle.)

⇒∠POR=2×80°=160°

In ∆POR, we have

∠POR+∠ORP+∠OPR=180°

But, we have ∠ORP=∠OPR         (Angles opposite to the equal sides in a triangle are equal.)

⇒160°+∠OPR+∠OPR=180°

⇒2∠OPR=180°−160°=20°

⇒∠OPR=20/2=10°

hope, this will help you.

Thank you______❤

_____________________________❤

Answered by masura8080
4

Answer:

We will get the angle OPR=10°.

Step-by-step explanation:

  • As per the question we have to evaluate the given data.

         Given data:- angle PQR=100°.

         To find:-  angle OPR=?

         Solution:-

  • Consider PR as a chord of the circle.  
  • Take any point S on the major arc of the circle.
  • PQRS is a cyclic quadrilateral.  

        ∠PQR + ∠PSR = 180° (Opposite angles of a cyclic quadrilateral)  

         ∠PSR = 180° − 100° = 80°

  • We know that the angle subtended by an arc at the center is double the angle subtended by it at any point on the remaining part of the circle.

        ∠POR = 2∠PSR = 2 (80°) = 160°

         OP = OR (Radii of the same circle)

      ∠OPR = ∠ORP (Angles opposite to equal sides of a triangle)

       [tex]=>\angle O P R+\angle O R P+\angle P O R=180^{\circ}\\ =>2 \angle O P R+160^{\circ}=180^{\circ} \\ =>2 \angle O P R=180^{\circ}-160^{\circ}=20^{\circ} \\ =>\angle O P R=10^{\circ} \end{array}[/tex]

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