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Exercise Question (Page 113)
Last updated at May 26, 2026 by Teachoo
Concyclicity of Points and Cyclic Quadrilateral
Class 9
Chapter 5 Class 9 - I’m Up and Down, and Round and Round (Ganita Manja
- Definitions
- Symmetries of Circle
- Number of Circles
- Exercise Set 5.1
- Think, Draw and Infer (Page 98)
- Angle Subtended by Chords
- Exercise Set 5.2
- Mid-points and Perpendicular Bisectors of Chords
- Exercise Set 5.3
- Distance of Chords from the Centre
- Exercise Set 5.4
- Distance of unequal chords from center
- Exercise Set 5.5
- Angle subtended by an arc
- Exercise Set 5.6
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Concyclicity of Points and Cyclic Quadrilateral
- Theorems (and their Proofs)
- End-of-Chapter Exercises
Transcript
Exercise Question (Page 113) A cyclic quadrilateral has angles measuring ∠A=80^∘, ∠B=110^∘,∠C=100^∘, and ∠D=70^∘. Can such a quadrilateral be drawn? Explain why or why not. We can do this without making the figure From Theorem 12 If two opposite angles of a quadrilateral add up to 180°, then the vertices of the quadrilateral lie on a circle, i.e., they are concyclic. Checking sum of opposite angles ∠ A + ∠ C = 80° + 100° = 180° ∠ B + ∠ D = 110° + 70° = 180° Si9nce sum of opposite angles is 180° It means ABCD form a cyclic quadrilateral Thus, our answer is Yes, cyclic quadrilateral can be formed
