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Numerical: Mensuration 2D — Circle MCQ - Practice Questions with Answers

Solve 15 Numerical: Mensuration 2D — Circle questions for RAS/RPSC preparation.

Practice questions

Q1The area of a circle is 154 cm². Using π = 22/7, identify the correct radius of the circle.

A 7 cm
B 14 cm
C 49 cm
D 24.5 cm
Explanation

For a circle, area A = πr². The given area is 154 cm² and π = 22/7. So, 154 = (22/7) × r². Hence r² = 154 × 7 ÷ 22. Since 154 ÷ 22 = 7, r² = 7 × 7 = 49. Therefore r = √49 = 7. This value is the radius, not the diameter. The correct radius of the circle is 7 cm.

Q2For a circle of radius 7 cm, match the quantities with their correct values: 1. diameter, 2. circumference, 3. area, 4. area of the semicircle. Take π = 22/7.

A 1-14 cm, 2-44 cm, 3-154 sq cm, 4-77 sq cm
B 1-7 cm, 2-44 cm, 3-154 sq cm, 4-77 sq cm
C 1-14 cm, 2-154 cm, 3-44 sq cm, 4-77 sq cm
D 1-14 cm, 2-44 cm, 3-154 sq cm, 4-154 sq cm
Explanation

For radius 7 cm, diameter = 2r = 14 cm. Circumference = 2πr = 2 × 22/7 × 7 = 44 cm. Area = πr² = 22/7 × 7 × 7 = 154 sq cm. A semicircle is half of the circle, so its area = 154 ÷ 2 = 77 sq cm. Thus the correct matching is 1-14 cm, 2-44 cm, 3-154 sq cm and 4-77 sq cm.

Q3A circular track has a diameter of 28 m. Using π = 22/7, what is its circumference?

A 44 m
B 88 m
C 176 m
D 616 m
Explanation

For the circumference of a circle, use C = πd when the diameter is given. Here d = 28 m and π = 22/7. So, C = (22/7) × 28. Since 28 ÷ 7 = 4, the circumference is 22 × 4 = 88. No radius squaring is needed because the question asks for the boundary length. Therefore, the circular track has a circumference of 88 m.

Q4The circumference of a circle is 44 cm. Taking π = 22/7, find its area.

A 154 sq cm
B 49 sq cm
C 44 sq cm
D 616 sq cm
Explanation

For a circle, circumference = 2πr. Here 44 = 2 × 22/7 × r, so 44 = 44r/7 and r = 7 cm. Now area = πr² = 22/7 × 7 × 7 = 22 × 7 = 154 sq cm. The given value 44 cm is only the circumference; after finding the radius, the area formula must be applied separately. Therefore, the area of the circle is 154 sq cm.

Q5The radius of a circle is increased from 7 cm to 14 cm. Taking π = 22/7, which of the following statements is incorrect?

A The circumference increases from 44 cm to 88 cm.
B The area increases from 154 sq cm to 616 sq cm.
C The increase in area is 462 sq cm.
D The circumference becomes 4 times the original circumference.
Explanation

Original radius = 7 cm. Original circumference = 2πr = 2 × 22/7 × 7 = 44 cm, and original area = 22/7 × 7 × 7 = 154 sq cm. New radius = 14 cm. New circumference = 2 × 22/7 × 14 = 88 cm, and new area = 22/7 × 14 × 14 = 616 sq cm. Increase in area = 616 − 154 = 462 sq cm. The circumference has become 88 ÷ 44 = 2 times, not 4 times. Hence statement D is incorrect.

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More questions

6For a circle of radius 21 cm, using π = 22/7, which statement is incorrect?

AThe diameter is 42 cm.
BThe circumference is 132 cm.
CThe area is 1386 sq cm.
DThe area of the semicircle is 1386 sq cm.

7Match List I with List II for circles, using π = 22/7. List I: P. radius 7 cm, Q. diameter 42 cm, R. circumference 88 cm, S. radius 21 cm. List II: 1. area 154 cm², 2. circumference 132 cm, 3. radius 14 cm, 4. area 1386 cm².

AP-1, Q-2, R-3, S-4
BP-1, Q-4, R-3, S-2
CP-3, Q-2, R-1, S-4
DP-1, Q-3, R-2, S-4

8Assertion: A circle with diameter 42 cm has an area of 1386 cm². Reason: The area of a circle is πr², and the radius is half of the diameter. Using π = 22/7, choose the correct option.

ABoth the assertion and the reason are true, and the reason correctly explains the assertion.
BBoth the assertion and the reason are true, but the reason does not explain the assertion.
CThe assertion is true, but the reason is false.
DThe assertion is false, but the reason is true.

9A circular flower bed has radius 14 m. A path of uniform width 7 m is made around it. Taking π = 22/7, find the area of the path.

A616 sq m
B770 sq m
C1386 sq m
D154 sq m

10The radius of a circular garden is 14 m. Using π = 22/7, find its area.

A616 m²
B88 m²
C176 m²
D154 m²

11Assertion: The circumference of a circle with radius 35 cm is 220 cm. Reason: Circumference of a circle is calculated by 2πr, and π = 22/7 is used here.

ABoth Assertion and Reason are true, and the Reason correctly explains the Assertion.
BBoth Assertion and Reason are true, but the Reason does not explain the Assertion.
CAssertion is true, but Reason is false.
DAssertion is false, but Reason is true.

12A circle has diameter 28 cm. Using π = 22/7, which statement is correct?

AIts circumference is 88 cm.
BIts area is 88 sq cm.
CIts circumference is 616 cm.
DIts radius is 28 cm.

13A sector of a circle has radius 21 cm and central angle 120°. Taking π = 22/7, which of the following statements is correct?

AThe area of the sector is 462 sq cm.
BThe arc length of the sector is 22 cm.
CThe area of the sector is 924 sq cm.
DThe area of the full circle is 462 sq cm.

14Match the quantities for a circle of radius 7 cm using π = 22/7: 1. Circumference, 2. Area, 3. Area of semicircle, 4. Area of quadrant.

A1-44 cm, 2-154 sq cm, 3-77 sq cm, 4-38.5 sq cm
B1-154 cm, 2-44 sq cm, 3-77 sq cm, 4-38.5 sq cm
C1-44 cm, 2-154 sq cm, 3-38.5 sq cm, 4-77 sq cm
D1-22 cm, 2-154 sq cm, 3-77 sq cm, 4-38.5 sq cm

15The radius of a circular garden is 14 cm. Using π = 22/7, find its area.

A616 sq cm
B88 sq cm
C196 sq cm
D154 sq cm

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