Mathematics · Quantitative Aptitude
Circle Geometry
250 Questions
Circle geometry focuses on the properties and dimensions of circles, including radius, diameter, circumference, and area calculations. Questions often involve concentric circles, sectors, and inscribed shapes. This topic frequently appears in quantitative aptitude sections of major competitive exams.
Area and circumferenceConcentric circlesCircle sectorsInscribed polygonsSemicircle area
Circle Geometry Questions
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154sq m
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151sq m
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153sq m
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152sq m
A
Correct answer
Explanation
The largest circle that fits inside a square is the inscribed circle, whose diameter equals the side of the square. With side 14m, radius = 7m. Area = πr² = π × 49 ≈ 154 sq m.
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Area of Square= Length Square
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Circumference of a circle=Pi (Diameter of circle)
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Area of Circle=2?r
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Area of triangle = ½b × h
C
Correct answer
Explanation
The formula for the area of a circle is $\pi r^2$. The expression $2\pi r$ represents the circumference of a circle, making this statement incorrect.
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(22/7)^2
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2x(22/7)
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(22/7)xR^2
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(22/7)x2^R
C
Correct answer
Explanation
The area of a circle is pi * R^2. Using 22/7 as the standard approximation for pi, the formula is (22/7) * R^2. Option 407792 is the correct representation of this area formula.
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2x(22/7)xR
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(22/7)xR^2
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(22/7)^2xR
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R^2
A
Correct answer
Explanation
The perimeter (circumference) of a circle is 2 * pi * R. Using 22/7 as an approximation for pi, the formula becomes 2 * (22/7) * R. Option 407798 correctly identifies this geometric formula.
B
Correct answer
Explanation
The largest square inscribed in a circle has a diagonal equal to the circle's diameter, which is 8 cm. The area of a square with diagonal $d$ is $d^2 / 2$. Thus, the area is $8^2 / 2 = 64 / 2 = 32$ square centimeters. Distractors represent incorrect formulas or area of the circumscribed square (64).
B
Correct answer
Explanation
A square circumscribing a circle of diameter 8 cm has a side length equal to the diameter of the circle, which is 8 cm. The perimeter of this square is $4 \times 8 = 32$ cm. Distractors like 16, 24, and 48 represent incorrect side-to-perimeter scaling or area calculations.
B
Correct answer
Explanation
Area is proportional to the square of the radius. If the radius becomes 0.9r, the area becomes (0.9)^2 = 0.81 of the original area. The diminution is 1 - 0.81 = 0.19, or 19%.
B
Correct answer
Explanation
Area is proportional to the square of the radius. If the radius becomes 0.9r, the area becomes (0.9)^2 = 0.81 of the original area. The decrease is 1 - 0.81 = 0.19, or 19%.
B
Correct answer
Explanation
The area of a full circle is πR². A quadrant is one-fourth of a circle, so its area is (πR²)/4.
A
Correct answer
Explanation
In mathematics, any finite number multiplied by zero results in zero. Regardless of the complexity of the areas calculated in the first two parts of the expression, the final multiplication by zero makes the product 0.
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the surface area of a sphere of diameter 22/7
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3.1415926
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the ratio of a circle’s diameter to its circumference.
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the ratio of a circle’s circumference to its diameter
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the ratio of a circle’s circumference to its radius.
D
Correct answer
Explanation
The formal mathematical definition of pi is the ratio of a circle's circumference (C) to its diameter (D), written as pi = C/D. Option C incorrectly reverses this ratio (diameter to circumference would give 1/pi), while option E incorrectly uses radius instead of diameter (C/radius would equal 2pi, not pi). Option B is only a decimal approximation.
C
Correct answer
Explanation
The largest circle that can be circumscribed in a rectangle must fit within the smaller dimension. For a 24x88 rectangle, the maximum diameter equals the smaller side (24), as the circle cannot exceed either dimension.
D
Correct answer
Explanation
For a square inside a circle, the diagonal equals the diameter. Diagonal = 2 * 5*sqrt(2) = 10*sqrt(2). Side = diagonal/sqrt(2) = 10. Area = 10^2 = 100 sq units.
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50/1.414
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50* 1.414
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50
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100 *1.414
C
Correct answer
Explanation
A square inscribed in a circle has a diagonal equal to the circle's diameter. With radius 5, the diameter is 10. The area of a square is (diagonal^2)/2, so (10^2)/2 = 100/2 = 50 square units.
B
Correct answer
Explanation
Area depends on the square of the radius (A = πr²). When radius becomes 0.9r (10% reduction), new area = π(0.9r)² = 0.81πr². The reduction is 1 - 0.81 = 0.19 = 19%. Option A (10%) would be true for circumference, not area. Option C (20%) ignores the squared relationship.