68 practice questions on Circles & Mensuration , sorted Easy → Hard. Try each one first, then open its answer page for the worked explanation. Want the full theory first? Read the Circles & Mensuration notes .
Cylinder, Cone, Sphere V=πr²h CSA=2πrh V=⅓πr²h CSA=πrl V=4/3πr³ SA=4πr² Three standard 3D solids and their key formulas: a cylinder's volume scales with the full height, a cone's volume is exactly one-third of the cylinder with the same base and height, and a sphere's volume and surface area both follow distinct r-based formulas worth memorising separately.
Easy - 20 questions Q10.
A sector of a circle with radius r and central angle theta (radians) has area:
A r × thetaB (1/2)r² thetaC 2r thetaD r² thetaShow answer & explanation →
Q16.
A tangent to a circle is:
A A line segment joining two points on the circleB A line touching circle at exactly one pointC A chord passing through the centre of the circleD A line cutting the circle at two distinct pointsShow answer & explanation →
Q18.
Heron formula for area of triangle with sides a, b, c: A = √[s(s-a)(s-b)(s-c)] where s =
A a + b + cB (a + b + c)/2C abcD a + bShow answer & explanation →
Q20.
Area of a trapezoid with parallel sides a and b, height h:
A (a+b) × hB (1/2)(a+b) × hC ab × hD (a-b) × hShow answer & explanation →
Medium - 20 questions Q21.
The common external tangents to two circles with radii r₁, r₂ and distance d between centres:
A 2, counted without checking whether the circles intersectB d/|r₁-r₂|, a ratio mistaken for a count of tangentsC 2 (if circles do not overlap externally)D Depends on d, since the count is assumed to vary continuously with itShow answer & explanation →
Q24.
Volume of a frustum (truncated cone) with radii R, r and height h:
A πh(R+r)/2, a simplified average radius formB (1/3)πh(R² + Rr + r²)C πh(R² + r²), omitting the cross termD (2/3)πh(R+r)², an incorrectly squared formShow answer & explanation →
Q28.
Volume of a hollow cylinder (external radius R, internal radius r, height h) is:
A πR²h - πr²hB π(R+r)hC πh(R-r)²D 2π(R+r)hShow answer & explanation →
Q32.
The lateral surface area of a pyramid with base perimeter P and slant height l:
A (1/2) P lB P × lC P + lD 2PlShow answer & explanation →
Q33.
A circle circumscribes an equilateral triangle of side a. Circumradius R =
A a/√3B a/√2C a/√3 × 2D a√3/3 = a/√3Show answer & explanation →
Q34.
A solid is formed by rotating a semicircle of radius r about the diameter. Volume =
A (2/3)πr³B (4/3)πr³C (1/3)πr³D πr³Show answer & explanation →
Q35.
Angle between a tangent and a chord drawn from the point of tangency:
A Equals the inscribed angle in alternate segmentB Is typically assumed to be 90°, mistaking it for the radius-tangent angleC Is typically assumed to be 45°, assuming the chord bisects the tangent angleD Equals the central angle subtended by the same chordShow answer & explanation →
Q36.
Two tangents drawn from an external point to a circle are:
A UnequalB Equal in lengthC Perpendicular to each otherD ParallelShow answer & explanation →
Q38.
The perimeter of a sector with radius 5 and angle 120° (use π ≈ 3.14):
A 10 + 10.47B 10 + 5.24C 5 + 10.47D 5 + 5.24Show answer & explanation →
Q39.
Volume of water in a hemispherical bowl of radius 7 cm when half full:
A (1/4)(4/3)πr³B (1/2)(2/3)πr³C (2/3)πr³/2 = (1/3)πr³D 718.67 cm³Show answer & explanation →
Hard - 28 questions Q41.
The power of a point P with respect to circle (centre O, radius r) is:
A |OP|² - r²B |OP| - rC r² - |OP|²D |OP| + rShow answer & explanation →
Q42.
Ptolemy theorem for a cyclic quadrilateral ABCD states:
A AC × BD = AB × CD + AD × BCB AC + BD = AB + CD, an additive but incorrect formC AC/BD = AB/CD, a ratio form that does not hold generallyD AC × BD = AB × AD, missing the CD term from the productShow answer & explanation →
Q43.
The angle between two chords intersecting inside a circle equals:
A Half the sum of intercepted arcsB Half the difference of intercepted arcsC The sum of intercepted arcsD The central angleShow answer & explanation →
Q44.
Area of circumscribed circle to a triangle with sides a, b, c (using sine rule R = abc/4K):
A π(abc/4K)²B π × abc/4KC πabc/2D 4πK/abcShow answer & explanation →
Q45.
If a sphere is cut by a plane at distance d from centre, the cross-section circle has radius:
A r - dB √(r² - d²)C r + dD √(r² + d²)Show answer & explanation →
Q46.
Isoperimetric inequality states: among all closed curves of fixed perimeter, the one enclosing maximum area is:
A SquareB Equilateral triangleC CircleD Regular hexagonShow answer & explanation →
Q47.
The radical axis of two non-concentric circles is:
A Parallel to the line of centresB Perpendicular to the line of centresC The same as the line of centresD The common chord extendedShow answer & explanation →
Q48.
For a frustum with top radius r, bottom radius R, height h, slant height l = √(h²+(R-r)²). Lateral SA =
A π(R+r)lB πl(R-r)C 2πl(R+r)D π(R²-r²)Show answer & explanation →
Q49.
Cavalieri principle: two solids have equal volume if:
A They have the same total surface areaB Every horizontal cross-section at same height has equal areaC They have the same height measured from base to apexD They share the same radius at their widest cross-sectionShow answer & explanation →
Q51.
The angle between a tangent to a circle and a secant from the same external point:
A Half the difference of intercepted arcsB Half the sum of intercepted arcsC Equals the central angleD 90°Show answer & explanation →
Q52.
A sphere of radius R is melted into n small spheres of radius r. Relation:
A R = nrB R³ = nr³C R² = nr²D nR = rShow answer & explanation →
Q53.
The nine-point circle of a triangle passes through:
A Midpoints of the three sides alone, excluding any other special pointsB Feet of the three altitudes alone, excluding the side midpointsC Midpoints of sides, feet of altitudes, and midpoints of vertex-to-orthocenter segmentsD The circumcentre and the incentre of the triangle, and nothing else besides those two pointsShow answer & explanation →
Q54.
Surface area of solid cylinder equals that of sphere. If cylinder has height = diameter (h=2r), find ratio of volumes:
A Vcylinder/Vsphere = 3/2B Vcylinder/Vsphere = 2/3C They are equalD Vcylinder/Vsphere = 4/3Show answer & explanation →
Q56.
In a circle of radius R, two chords AB and CD intersect at P. Then PA × PB =
A PC × PDB (PC + PD)/2C PC² + PD²D PC - PDShow answer & explanation →
Q57.
The equation of a circle with centre at the origin and radius 5 is:
A x² + y² = 25B x² + y² = 5C x² − y² = 25D x + y = 5Show answer & explanation →
Q63.
The circles x² + y² = 9 and x² + y² − 8x + 7 = 0 are:
A Touching externallyB Intersecting at two pointsC One inside the otherD ConcentricShow answer & explanation →
Q68.
A sphere and a cube have equal total surface areas. The ratio of the volume of the sphere to that of the cube is:
A √(π/6)B √(6/π)C 6/πD π/6Show answer & explanation →