CBSE Class 10 Mathematics Chapter 10 Circles — 20 MCQs with Answers
Chapter 10 Circles in CBSE Class 10 Mathematics introduces elegant theorems about angles, chords, and cyclic quadrilaterals that have stood the test of time since Euclid. The 2025 board paper typically carries 4-5 marks from this chapter, often as MCQs (1 mark each) or assertion-reason questions. These 20 MCQs mirror the exact difficulty spectrum you will face—from direct recall of the angle-at-centre theorem to multi-step cyclic quadrilateral problems and HOTS questions that test your ability to combine multiple concepts. Solve them under timed conditions, check your answers immediately, and note the reasoning. This active practice builds both speed and confidence for the board exam.
Key takeaways
- ✓The angle subtended by a chord at the centre is exactly twice the angle subtended at any point on the circumference on the same arc.
- ✓All angles in the same segment of a circle (formed by a chord) are equal, regardless of where the point lies on that arc.
- ✓Any angle subtended by a diameter from a point on the circumference is always 90°, making it a reliable test for right angles in circle problems.
- ✓In a cyclic quadrilateral, opposite angles are supplementary—they always add up to 180°—and this property uniquely defines cyclic quadrilaterals.
- ✓The converse is equally powerful: if opposite angles of any quadrilateral sum to 180°, the four vertices must lie on a circle, proving it is cyclic.
- ✓MCQs in CBSE Mathematics papers carry 1 mark each and test quick recall, formula application, and logical reasoning under time pressure.
- ✓Practising 15-20 MCQs daily from each chapter sharpens pattern recognition and reduces silly errors in board exams.
Angle Subtended by Chord at Centre and Circumference — MCQs
- **Q1.** A chord PQ of a circle with centre O subtends an angle of 60° at point R on the major arc. What is the measure of ∠POQ? (A) 30° (B) 60° (C) 120° (D) 180° **Answer: (C) 120°** — By the angle-at-centre theorem, ∠POQ = 2 × ∠PRQ = 2 × 60° = 120°.
- **Q2.** In a circle, a chord AB subtends an angle of 80° at the centre O. The angle subtended by the same chord at a point C on the remaining part of the circle is: (A) 40° (B) 80° (C) 100° (D) 160° **Answer: (A) 40°** — Angle at circumference = half the central angle = 80° ÷ 2 = 40°.
- **Q3.** If a chord subtends an angle of 90° at the centre of a circle, what is the angle it subtends at any point on the major arc? (A) 45° (B) 90° (C) 135° (D) 180° **Answer: (A) 45°** — Angle at circumference = 90° ÷ 2 = 45° (always half the central angle).
- **Q4.** A chord MN of a circle subtends an angle of 50° at a point on the minor arc. The angle subtended by the same chord at the centre is: (A) 25° (B) 50° (C) 100° (D) 130° **Answer: (C) 100°** — First, angle on major arc = 180° − 50° = 130°; then central angle = 2 × 130° = 260°? No—angle on minor arc is external, so central = 2 × 50° = 100°.
Angles in the Same Segment — MCQs
- **Q5.** Points A, B, C, D lie on a circle such that chord AC subtends ∠ABC = 65° and ∠ADC is on the same arc. The measure of ∠ADC is: (A) 32.5° (B) 65° (C) 115° (D) 130° **Answer: (B) 65°** — Angles in the same segment (same arc) are equal, so ∠ADC = ∠ABC = 65°.
- **Q6.** In a circle, a chord PQ subtends ∠PRQ = 40° at point R and ∠PSQ at point S, both on the major arc. What is ∠PSQ? (A) 20° (B) 40° (C) 80° (D) 140° **Answer: (B) 40°** — Both R and S lie on the same arc, so ∠PSQ = ∠PRQ = 40° (angles in same segment).
- **Q7.** If ∠BAC = 55° and ∠BDC are angles subtended by chord BC at points A and D on the same side of BC, then ∠BDC is: (A) 27.5° (B) 55° (C) 110° (D) 125° **Answer: (B) 55°** — Angles in the same segment are equal.
- **Q8.** A chord divides a circle into two arcs. If an angle of 48° is formed at one point on the major arc, the angle at another point on the same major arc is: (A) 24° (B) 48° (C) 96° (D) 132° **Answer: (B) 48°** — Angles in the same segment remain constant at 48°.
Angle in a Semicircle and Diameter Properties — MCQs
- **Q9.** AB is a diameter of a circle with centre O. If C is any point on the circle (not A or B), then ∠ACB is: (A) 45° (B) 60° (C) 90° (D) 180° **Answer: (C) 90°** — Angle in a semicircle is always 90°.
- **Q10.** In a circle, PQ is a diameter and R is a point on the circle. If ∠PRQ = 90°, which statement is true? (A) PR is a diameter (B) QR is a diameter (C) PQ is a diameter (D) Triangle PQR is equilateral **Answer: (C) PQ is a diameter** — Since ∠PRQ = 90°, PQ must be the diameter (angle in semicircle property).
- **Q11.** A circle has diameter 10 cm. A point M on the circle subtends an angle with the endpoints of the diameter. This angle measures: (A) 30° (B) 45° (C) 60° (D) 90° **Answer: (D) 90°** — Any point on the circle forms a 90° angle with the diameter endpoints.
- **Q12.** If AB is a diameter and ∠CAB = 35° where C is on the circle, then ∠ABC is: (A) 35° (B) 45° (C) 55° (D) 90° **Answer: (C) 55°** — ∠ACB = 90° (semicircle), so in △ABC: 35° + ∠ABC + 90° = 180° → ∠ABC = 55°.
Cyclic Quadrilateral Properties — MCQs
- **Q13.** ABCD is a cyclic quadrilateral. If ∠A = 70° and ∠C = 110°, which property is satisfied? (A) Adjacent angles are equal (B) Opposite angles are supplementary (C) All angles are equal (D) Diagonals are equal **Answer: (B) Opposite angles are supplementary** — 70° + 110° = 180°, confirming the cyclic property.
- **Q14.** In cyclic quadrilateral PQRS, ∠P = 85°. What is ∠R? (A) 85° (B) 90° (C) 95° (D) 180° **Answer: (C) 95°** — Opposite angles sum to 180°, so ∠R = 180° − 85° = 95°.
- **Q15.** If opposite angles of a quadrilateral are 78° and 102°, the quadrilateral is: (A) a rectangle (B) a cyclic quadrilateral (C) a rhombus (D) none of these **Answer: (B) a cyclic quadrilateral** — 78° + 102° = 180°, satisfying the converse of the cyclic quadrilateral theorem.
- **Q16.** In cyclic quadrilateral KLMN, ∠K = 2x, ∠L = 3x, ∠M = 4x, ∠N = 3x. Find x. (A) 15° (B) 20° (C) 25° (D) 30° **Answer: (D) 30°** — Sum = 2x + 3x + 4x + 3x = 12x = 360° → x = 30°; verify: ∠K + ∠M = 60° + 120° = 180° ✓.
Application, HOTS, and Assertion-Reason MCQs
- **Q17.** Assertion (A): If a quadrilateral has one pair of opposite angles summing to 180°, it is cyclic. Reason (R): All cyclic quadrilaterals have both pairs of opposite angles summing to 180°. (A) Both A and R are true, R is correct explanation (B) Both true, R is not correct explanation (C) A true, R false (D) A false, R true **Answer: (D) A false, R true** — One pair summing to 180° is insufficient; both pairs must sum to 180° to be cyclic.
- **Q18.** A chord of a circle subtends 120° at the centre. The angle subtended at a point on the minor arc is: (A) 30° (B) 60° (C) 120° (D) 150° **Answer: (D) 150°** — Angle on major arc = 120° ÷ 2 = 60°; on minor arc = 180° − 60° = 150° (angles on opposite arcs are supplementary).
- **Q19.** In cyclic quadrilateral ABCD, ∠A = 3∠C. Find ∠A. (A) 45° (B) 60° (C) 90° (D) 135° **Answer: (D) 135°** — Let ∠C = x, then ∠A = 3x. Since ∠A + ∠C = 180°, 3x + x = 180° → x = 45°, ∠A = 3 × 45° = 135°.
- **Q20.** A circle passes through vertices of a triangle ABC. If ∠BAC = 50° and BC is a diameter, find ∠ABC. (A) 40° (B) 50° (C) 90° (D) 130° **Answer: (A) 40°** — Since BC is diameter, ∠BAC is inscribed in semicircle, so ∠BCA = 90°. In △ABC: 50° + ∠ABC + 90° = 180° → ∠ABC = 40°.
How to Attempt MCQs in the CBSE Paper — Strategy Section
- **Read the question stem carefully:** Underline keywords like 'cyclic', 'diameter', 'major arc', 'minor arc' to avoid misreading the setup.
- **Draw a quick sketch:** Even a rough circle with labeled points takes 10 seconds and prevents visualization errors in angle problems.
- **Use elimination:** If you can rule out two options confidently, your guess between the remaining two has 50% accuracy.
- **Verify by substitution:** After choosing an answer, plug it back into the question to see if it satisfies all conditions—this catches calculation slips.
- **Watch for 'NOT' and 'EXCEPT':** CBSE occasionally phrases questions negatively; highlight these words so you do not pick the correct statement by mistake.
- **Manage time ruthlessly:** Spend no more than 60 seconds per MCQ. If stuck, mark it and move on—returning later often brings clarity.
- **Assertion-Reason protocol:** First decide if A is true, then if R is true, then if R explains A. Many students lose marks by not following this sequence.
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Frequently asked questions
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What is the difference between angles on the major arc and minor arc?+
Can a rectangle be a cyclic quadrilateral?+
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