Geometry Questions

Multiple choice
  1. 10

  2. 5

  3. 20

  4. 25

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

Using the property that perpendicular distance from center to a chord bisects the chord: half-chord = √(r² - d²). For first chord: 12 = √(r² - 5²), so 144 = r² - 25, giving r² = 169, r = 13 cm. For second chord at 12 cm: half-chord = √(13² - 12²) = √(169 - 144) = √25 = 5. Therefore, full chord length = 2 × 5 = 10 cm.

Multiple choice
  1. 1440

  2. 360

  3. 1260

  4. 900

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

Using the alternate segment theorem: ∠BPC = 180° - ∠BAC. But ∠BAC = 54° (likely notation error - should be 54° not 540°). So ∠BPC = 180° - 54° = 126°. The angle between the tangents equals the supplement of the angle between the chords. In quadrilateral ABPC, opposite angles sum to 180°.

Multiple choice
  1. 8 cm./सेमी.

  2. 6 cm./सेमी.

  3. 10 cm./सेमी.

  4. 9 cm./सेमी.

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

For similar triangles, ratio of perimeters = ratio of corresponding sides. Perimeter ratio = 30:20 = 3:2. So corresponding side ratio is 3:2. If first triangle's side is 12 cm, second's corresponding side = 12×2/3 = 8 cm. This uses the fundamental property that similar triangles have proportional corresponding dimensions.

Multiple choice
  1. 3:4

  2. 4:3

  3. 2:3

  4. 4:5

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

For similar triangles, the ratio of their areas equals the square of the ratio of their corresponding sides. If area ratio is 9:16, then side ratio = √9:√16 = 3:4. This is because area scales with the square of linear dimensions - if sides are in ratio k, areas are in ratio k². This property applies to all similar 2D figures, not just triangles. Option C (2:3) would give area ratio 4:9, and D (4:5) would give 16:25.

Multiple choice
  1. 6 cm./सेमी

  2. 7 cm./सेमी

  3. 8 cm./सेमी

  4. 5.5 cm./सेमी

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

For a circle of radius 5 cm, chord length 8 cm gives perpendicular distance from center = √(5² - 4²) = 3 cm (half the chord is 4 cm). Both chords are parallel and equidistant from center, so distance between chords = 3 + 3 = 6 cm.

Multiple choice
  1. 8 cm

  2. 10 cm

  3. 6 cm

  4. 12 cm

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

For two circles with radii r = 2 cm and R = 8 cm, the direct common tangent length L = 8 cm. Using the formula L = √(d² - (R - r)²) where d is the distance between centers: 8 = √(d² - (8 - 2)²) = √(d² - 36). Squaring: 64 = d² - 36, so d² = 100, and d = 10 cm. Option B is correct. Options A (8 cm), C (6 cm), and D (12 cm) are incorrect distances.

Multiple choice
  1. 10.7 cm./सेमी.

  2. 16.2 cm./सेमी.

  3. 7.7 cm./सेमी.

  4. 7.2 cm./सेमी.

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

In a tangential quadrilateral, sum of opposite sides are equal: AB + CD = BC + DA. So 7 + 9.2 = 8.5 + DA, giving DA = 7.7 cm.

Multiple choice
  1. 3+ 8 :3− 8

  2. 3+ 10 :3− 10

  3. 3+ 3 :3− 3

  4. 3: 3

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

In a circle, when a diameter intersects a chord perpendicularly at P: AP × BP = (chord half-length)² = 1² = 1. Also AP + BP = 2r = 6. Solving: If AP = x, BP = 6-x, then x(6-x) = 1, giving x² - 6x + 1 = 0. Solving: x = (6 ± √(36-4))/2 = (6 ± √32)/2 = 3 ± 2√2 = 3 ± √8. Since AP > BP, AP = 3 + √8 and BP = 3 - √8, giving ratio (3+√8):(3-√8).

Multiple choice
  1. 6 cm./सेमी.

  2. 12 cm./सेमी.

  3. 18 cm./सेमी.

  4. 24 cm./सेमी.

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

Area of triangle ABC = 108 cm². Distance of base BC from centroid G = 6 cm. The centroid divides the median in ratio 2:1, so the height h from A to BC satisfies h/3 = 6, giving h = 18 cm. Area = (1/2) × base × height = (1/2) × b × 18 = 108, so base b = 108 × 2/18 = 12 cm. The equal sides' information is consistent but not needed for this calculation.

Multiple choice
  1. n (2r - n) = m2

  2. n (2r - n) = 4m2

  3. 2n (2r - n) = m2

  4. 4n (2r - n) = m2

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

The relationship between chord length m, sagitta (height) n, and radius r in a circle is m² = 4n(2r - n). This formula comes from the fact that the radius to the chord's midpoint is perpendicular to the chord, forming a right triangle with half the chord (m/2) and the distance from center to chord (r-n). By the Pythagorean theorem: (m/2)² + (r-n)² = r², which simplifies to m² = 4n(2r - n). Option A is incorrect as it's missing the factor of 4, and option C is incorrect as it has 2n instead of 4n.

Multiple choice
  1. Only II and III

  2. All statements together are sufficient

  3. None of these

  4. I and II or III

  5. All statements together are not sufficient

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

Statement II gives one angle as 60°, which in a right triangle means the other acute angle is 30°. Statement III gives the hypotenuse as 4 cm. In a 30-60-90 triangle, if hypotenuse = 4 cm, then shorter side = 2 cm and longer side = 2√3 cm. Area = (1/2) × 2 × 2√3 = 2√3 cm². Statement I about perimeter being 5 times the base is unnecessary.

Multiple choice
  1. 12 cm./सेमी.

  2. 11 cm./सेमी.

  3. 17 cm./सेमी.

  4. 10 cm./सेमी.

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

For direct common tangent to circles with radii r₁=8, r₂=3 and center distance d=13, use SR² = d² - (r₁-r₂)². SR² = 13² - (8-3)² = 169 - 25 = 144. Therefore SR = √144 = 12 cm.

Multiple choice
  1. 6 5 7

  2. 12 2 7

  3. 3 5 7

  4. 10 2 7

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

In a circle of radius 7, chord PB = 12. Distance from center O to chord: d = √(7² - 6²) = √13. Coordinate approach: Place circle at origin, AB as x-axis. If P = (x,y) on circle and PB is chord to B = (7,0), with PB = 12, we find PN (distance from P to diameter AB). Using circle geometry: PN = (OP × PB)/radius = (7 × 12)/7 = 72/7 = 10 2/7.

Multiple choice
  1. 4 cm.

  2. 6 cm.

  3. 5 cm.

  4. 8 cm.

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

OC is perpendicular to chord AB, so C bisects AB. AC = 4 cm. Let radius = r, then OC = r - CD = r - 2. In right triangle OAC: OA² = OC² + AC², so r² = (r - 2)² + 4² = r² - 4r + 4 + 16. Cancelling r²: 0 = -4r + 20, giving r = 5 cm. This matches option C.

Multiple choice
  1. 10 cm./सेमी.

  2. 6 cm./सेमी.

  3. 5 cm./सेमी.

  4. 4 cm./सेमी.

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

Since OP ⟂ AB, OP bisects AB at M. So AM = MB = 4 cm. In right triangle OMP: OM² + MP² = OP². Also OM² + AM² = OA² (radius). Given AB = 8 cm, so AM = 4 cm. MP = 2 cm. OM² = OA² - 16. Also OM² + 4 = (OA - 2)². Solving: OA² - 16 + 4 = OA² - 4OA + 4, so OA² - 12 = OA² - 4OA + 4, therefore 4OA = 16 and OA = 5 cm. Options A, B, D are calculation errors.