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Chapter 9 of 12
Flashcards

Circles

Gujarat Board · Class 9 · Mathematics

Flashcards for Circles — Gujarat Board Class 9 Mathematics. Quick Q&A cards covering key concepts, definitions, and formulas.

45 questions20 flashcards5 concepts
20 Flashcards
Card 1Angle Subtended by Chord

What is the angle subtended by a chord PQ at point R?

Answer

The angle subtended by chord PQ at point R is ∠PRQ, formed by joining point R to both endpoints P and Q of the chord. If R is at the center, it's called the angle subtended at the center. If R is on t

Card 2Equal Chords and Angles

State Theorem 9.1 about equal chords and angles at center.

Answer

Theorem 9.1: Equal chords of a circle subtend equal angles at the centre. This means if two chords AB and CD are equal in length, then ∠AOB = ∠COD, where O is the center of the circle.

Card 3Equal Chords and Angles

What is the converse of Theorem 9.1?

Answer

Theorem 9.2: If the angles subtended by chords of a circle at the centre are equal, then the chords are equal. This means if ∠AOB = ∠COD, then chord AB = chord CD.

Card 4Perpendicular from Center

State Theorem 9.3 about perpendicular from center to chord.

Answer

Theorem 9.3: The perpendicular from the centre of a circle to a chord bisects the chord. If OM ⊥ AB where O is center and M is on chord AB, then AM = MB.

Card 5Perpendicular from Center

What is the converse of Theorem 9.3?

Answer

Theorem 9.4: The line drawn through the centre of a circle to bisect a chord is perpendicular to the chord. If OM bisects chord AB, then OM ⊥ AB.

Card 6Distance from Center

How is the distance of a line from a point defined?

Answer

The distance of a line from a point is the length of the perpendicular from the point to the line. This perpendicular is the shortest distance between the point and the line. If the point lies on the

Card 7Equal Chords and Distance

State Theorem 9.5 about equal chords and their distances from center.

Answer

Theorem 9.5: Equal chords of a circle (or of congruent circles) are equidistant from the centre (or centres). If AB = CD, then the perpendicular distances from center O to both chords are equal.

Card 8Equal Chords and Distance

What is the converse of Theorem 9.5?

Answer

Theorem 9.6: Chords equidistant from the centre of a circle are equal in length. If two chords are at the same perpendicular distance from the center, then the chords are equal.

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Frequently Asked Questions

What are the important topics in Circles for Gujarat Board Class 9 Mathematics?

Circles covers several key topics that are frequently asked in Gujarat Board Class 9 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.

Start by understanding all key concepts. Practise previous year questions from this chapter. Revise formulas and definitions regularly. Use flashcards for quick revision before the exam.

There are 20 flashcards for Circles covering key definitions, formulas, and concepts. Use them daily for 10–15 minutes for best results.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.