CBSE Class 10 Areas Related to Circles MCQs – Area of Sector and Arc Length
CBSE Class 10 Areas Related to Circles MCQs – Area of Sector & Arc Length
Class: 10 | Subject: Mathematics
Chapter 11: Areas Related to Circles
Board: CBSE Board Examination (Strictly Based on Latest NCERT Curriculum)
1. The formula for area of a sector of angle θ° is:
Correct Answer: A. (θ/360) × πr²
Explanation: Area of sector = (Central angle/360°) × πr².
Explanation: Area of sector = (Central angle/360°) × πr².
2. The formula for length of arc of angle θ° is:
Correct Answer: A. (θ/360) × 2πr
Explanation: Arc length is proportional to the central angle.
Explanation: Arc length is proportional to the central angle.
3. Find area of sector of radius 7 cm and angle 90°.
Correct Answer: A. 38.5 cm²
Explanation: Area = (90/360)×π×7² = (1/4)×(22/7)×49 = 38.5 cm².
Explanation: Area = (90/360)×π×7² = (1/4)×(22/7)×49 = 38.5 cm².
4. Find arc length for radius 7 cm and angle 180°.
Correct Answer: A. 22 cm
Explanation: Arc length = (180/360)×2π×7 = π×7 = 22 cm.
Explanation: Arc length = (180/360)×2π×7 = π×7 = 22 cm.
5. If θ = 60° and r = 14 cm, arc length is:
Correct: A. 44/3 cm
Explanation: (60/360)×2π×14 = (1/6)×2×22/7×14 = 44/3 cm.
Explanation: (60/360)×2π×14 = (1/6)×2×22/7×14 = 44/3 cm.
6. If area of full circle is 154 cm², radius is:
Correct: A. 7 cm
Explanation: πr²=154 ⇒ r²=49 ⇒ r=7.
Explanation: πr²=154 ⇒ r²=49 ⇒ r=7.
7. Sector area for 120° of radius 7 cm:
Correct: A. 51.33 cm²
Explanation: (120/360)×154 = 51.33 cm².
Explanation: (120/360)×154 = 51.33 cm².
8. If arc length equals radius, angle is:
Correct: A. 57.3°
Explanation: Using radian concept L=rθ ⇒ θ=1 rad ≈57.3°.
Explanation: Using radian concept L=rθ ⇒ θ=1 rad ≈57.3°.
9. Full circle area formula:
Correct:B.πr²
Explanation: Standard formula.
Explanation: Standard formula.
10. Perimeter of sector includes:
Correct:B.Two radii + arc
Explanation: Perimeter = arc length + 2r.
Explanation: Perimeter = arc length + 2r.
11. If r doubles, area becomes:
Correct:C.Four times
Explanation: Area ∝ r².
Explanation: Area ∝ r².
12. If θ doubles, sector area becomes:
Correct:A.Double
Explanation: Area ∝ θ.
Explanation: Area ∝ θ.
13. Circumference formula:
Correct:B.2πr
Explanation: Standard formula.
Explanation: Standard formula.
14. Sector 360° equals:
Correct:B.Full circle
Explanation: 360° represents whole circle.
Explanation: 360° represents whole circle.
15. Area of semicircle:
Correct:B.½πr²
Explanation: Half of full circle.
Explanation: Half of full circle.
16. Arc of 90° equals what fraction?
Correct:B.1/4
Explanation: 90/360 = 1/4.
Explanation: 90/360 = 1/4.
17. If r=21 cm, full circumference is:
Correct:A.132 cm
Explanation: 2πr = 2×22/7×21=132.
Explanation: 2πr = 2×22/7×21=132.
18. If arc length is 44 cm and r=7 cm, angle is:
Correct:A.180°
Explanation: Using L=(θ/360)2πr ⇒ solve gives 180°.
Explanation: Using L=(θ/360)2πr ⇒ solve gives 180°.
19. Area depends on:
Correct:C.Both r & θ
Explanation: Formula contains both.
Explanation: Formula contains both.
20. If θ=0°, sector area is:
Correct:A.0
Explanation: No angle means no area.
Explanation: No angle means no area.
