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Circles in the Wild
Last updated at May 26, 2026 by Teachoo
Class 9
Chapter 5 Class 9 - I’m Up and Down, and Round and Round (Ganita Manja
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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
- Concyclicity of Points and Cyclic Quadrilateral
- Theorems (and their Proofs)
- End-of-Chapter Exercises
Transcript
Circles in the Wild Circles aren't just shapes drawn on paper; they are everywhere in nature. Image 1 (Left): These are concentric circles (circles that share the same center) formed by raindrops hitting a still body of water. The impact pushes the water outward evenly in all directions. Image 2 (Middle): This is a cross-section of a tree trunk. As a tree grows, it adds a new layer of wood each year, creating circular "growth rings." Image 3 (Right): This is the face of a sunflower. The florets (which become seeds) grow from the center outward in a spiral pattern that creates a nearly perfect circular shape.
