Geometry Questions

Multiple choice
  1. 1/2

  2. √3

  3. 1/√3

  4. 2/√3

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Area of equilateral triangle = (√3/4) × side². Given area = √3, so (√3/4) × a² = √3. Dividing by √3: a²/4 = 1, so a² = 4 and a = 2 cm. In equilateral triangle, median = altitude = (√3/2) × side = (√3/2) × 2 = √3 cm. Centroid divides median in ratio 2:1 (vertex to centroid : centroid to midpoint). OD = (1/3) × AD = (1/3) × √3 = 1/√3 cm.

Multiple choice
  1. 12 cm

  2. 23 cm

  3. 12.5 cm

  4. 25 cm

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The tangent at P is perpendicular to radius OP, so triangle OPQ is right-angled at P. OP = 7 cm (radius), PQ = 24 cm (given). Using Pythagoras theorem: OQ² = OP² + PQ² = 7² + 24² = 49 + 576 = 625. Therefore OQ = sqrt(625) = 25 cm. This is a standard application of tangent-radius property and Pythagoras theorem.

Multiple choice
  1. 10 cm./सेमी.

  2. 8.5 cm./सेमी.

  3. 9 cm./सेमी.

  4. 9.5 cm./सेमी.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Shortest side is 6 cm. Using Apollonius theorem for median: m² = (2b² + 2c² - a²)/4 where a is the side with median. Here m² = (2×64 + 2×100 - 36)/4 = 292/4 = 73. So m = √73 ≈ 8.54 cm ≈ 8.5 cm.

Multiple choice
  1. 10

  2. 8

  3. 6

  4. 4

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

For a circle of radius 5 cm (diameter 10 cm), a chord of length 6 cm is 3 cm from each end (half of chord length). Using the perpendicular from center to the chord, we get a right triangle with hypotenuse = 5 cm and one leg = 3 cm. The distance from center = √(5² - 3²) = √(25 - 9) = √16 = 4 cm. This uses the property that the perpendicular from the center bisects the chord.

Multiple choice
  1. 2

  2. 4

  3. 3

  4. 1

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When two circles touch externally at one point, there are exactly 3 common tangents: 2 direct common tangents (which do not intersect the line joining centers) and 1 transverse common tangent (which passes through the point of contact). The question asks for direct common tangents, but the expected answer appears to include all common tangents.

Multiple choice
  1. 18 cm

  2. 11 cm

  3. 16.8 cm

  4. 17 cm

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

By the intersecting chords theorem: PD × DQ = SD × DR. Given PD = 8.4 cm, DQ = 2.4 cm, SD = 1.2 cm. So 8.4 × 2.4 = 1.2 × DR, giving DR = 20.16/1.2 = 16.8 cm. Total RS = SD + DR = 1.2 + 16.8 = 18 cm. Option A is correct.

Multiple choice
  1. 3 cm

  2. 4 cm

  3. 5 cm

  4. 2.5 cm

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In a right triangle, the circumcenter is the midpoint of the hypotenuse. For triangle ABC with angle B = 90°, AC is the hypotenuse. AC = sqrt(3² + 4²) = 5 cm by Pythagoras theorem. The circumcenter D is the midpoint of AC, so BD = half of AC = 5/2 = 2.5 cm. This is the circumradius of a right triangle.

Multiple choice
  1. 200

  2. 300

  3. 400

  4. 600

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This geometry problem requires analyzing angles in a circle with chord AB and point D on the circumference. Given BC = OD and ∠BCD = 20°, we can work through isosceles triangles and circle theorems to find that ∠AOD = 60°. The large values (200°, 300°, 400°, 600°) suggest this may use a different notation or the diagram is needed for clarity.

Multiple choice
  1. 28

  2. 38

  3. 12

  4. 13

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For an incircle touching sides AB, BC, CA at P, Q, R respectively: AP = AR = 7 cm (tangents from A), CR = CQ = 6 cm (tangents from C), BQ = BP = 12 cm (tangents from B, since BC = BQ+CQ = BQ+6 = 12, so BQ = 6). Wait, BC = 12 is given. BQ+CQ = 12. If CQ=6, then BQ=6. So BP=6, BQ=6. Perimeter = AB+BC+CA = (AP+PB)+(BQ+CQ)+(CR+RA) = (7+6)+(6+6)+(6+7) = 13+12+13 = 38 cm. ✓

Multiple choice
  1. $\(30^o\)$
  2. $\(20^o\)$
  3. $\(10^o\)$
  4. $\(15^o\)$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Arc length = radius × angle (in radians). Let first circle have radius r and angle 60°. Its arc length = r × 60°. Second circle has radius 3r and unknown angle θ. Its arc length = 3r × θ. Given that first arc is double the second: r × 60° = 2(3r × θ). Solving: 60° = 6θ, so θ = 10°.