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Chapter 6 of 14
Flashcards

Circles

Karnataka Board · Class 10 · Mathematics

Flashcards for Circles — Karnataka Board Class 10 Mathematics. Quick Q&A cards covering key concepts, definitions, and formulas.

45 questions20 flashcards5 concepts
20 Flashcards
Card 1Tangent Properties

A circle has radius 5 cm. A tangent is drawn from an external point P such that the length of tangent is 12 cm. Find the distance from P to the center of the circle.

Answer

Step 1: Draw diagram - Circle with center O, radius = 5 cm, tangent PT = 12 cm Step 2: Use tangent property - Tangent is perpendicular to radius at point of contact Step 3: Apply Pythagoras theorem in

Card 2Tangent Properties

From point A outside a circle, two tangents AB and AC are drawn. If AB = 8 cm and ∠BAC = 60°, find the radius of the circle.

Answer

Step 1: Given - AB = AC = 8 cm (tangents from external point are equal), ∠BAC = 60° Step 2: In triangle ABC, AB = AC, so it's isosceles ∠ABC = ∠ACB = (180° - 60°)/2 = 60° Therefore, triangle ABC

Card 3Chord Properties

A chord PQ of length 16 cm is at a distance of 6 cm from the center of a circle. Find the radius of the circle.

Answer

Step 1: Draw perpendicular from center O to chord PQ, meeting at M Step 2: Perpendicular from center bisects the chord PM = MQ = 16/2 = 8 cm Step 3: Given - OM = 6 cm (distance from center to chord

Card 4Concentric Circles

Two concentric circles have radii 3 cm and 5 cm. A chord of the outer circle touches the inner circle. Find the length of this chord.

Answer

Step 1: Let O be common center, AB be chord of outer circle touching inner circle at P Step 2: Since AB touches inner circle at P, OP ⊥ AB OP = radius of inner circle = 3 cm Step 3: OP bisects chor

Card 5Tangent Formula

When do you use the formula: (Length of tangent)² = (Distance from external point)² - (Radius)²?

Answer

Use this formula when: - Finding tangent length from an external point - Given distance from external point to center and radius Example: Point P is 13 cm from center O of a circle with radius 5 cm T

Card 6Tangent Theorem

Prove that tangents drawn from an external point to a circle are equal in length.

Answer

Given: Circle with center O, external point P, tangents PA and PB To prove: PA = PB Proof: Step 1: Join OP, OA, OB Step 2: ∠OAP = 90° (tangent ⊥ radius) ∠OBP = 90° (tangent ⊥ radius) Step 3: In ri

Card 7Circumscribed Quadrilateral

A quadrilateral ABCD is circumscribed about a circle. If AB = 6 cm, BC = 7 cm, CD = 4 cm, find AD.

Answer

Step 1: For a quadrilateral circumscribed about a circle (tangential quadrilateral): Sum of opposite sides are equal AB + CD = BC + AD Step 2: Substitute given values: 6 + 4 = 7 + AD 10 =

Card 8Chord Properties

In a circle with center O, chord AB = 12 cm and chord CD = 16 cm. If AB is 8 cm from center, find the distance of CD from center.

Answer

Step 1: For chord AB - let M be foot of perpendicular from O OM ⊥ AB, so AM = MB = 12/2 = 6 cm Given: OM = 8 cm Step 2: Find radius using right triangle OMA: OA² = OM² + AM² OA² = 8² + 6²

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Frequently Asked Questions

What are the important topics in Circles for Karnataka Board Class 10 Mathematics?

Circles covers several key topics that are frequently asked in Karnataka Board Class 10 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.