Geometry Questions

Multiple choice
  1. ${25 ^0}$
  2. ${30^0}$
  3. ${40^0}$
  4. ${50 ^0}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In triangle OAP, angle OAP = 90 degrees. Angle APO = 50/2 = 25 degrees. In triangle OAP, angle AOP = 180 - 90 - 25 = 65 degrees. In triangle OAB, OA = OB (radii), so angle OAB = angle OBA. Angle AOB = 360 - 2 * angle AOP = 360 - 130 = 230? No, angle AOB = 180 - 50 = 130. Angle OAB = (180 - 130)/2 = 25 degrees.

Multiple choice
  1. $2$
  2. $3$
  3. $4$
  4. $0$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The sum of the radii of the two circles is 3 cm + 3 cm = 6 cm. Since the distance between their centers is 8 cm, which is greater than the sum of their radii, the two circles lie completely outside each other without intersecting. For two such disjoint circles, there are exactly 4 common tangents: 2 direct and 2 transverse.

Multiple choice
  1. $1$
  2. $2$
  3. Infinite

  4. Zero

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

A line can be tangent to infinitely many circles (e.g., circles of varying radii with centers at varying distances from the line).

Multiple choice
  1. $ [-13/8 , 13/8]$
  2. $ > 13/8\ Or\ < -13/8$
  3. $(1, 13/8)$
  4. none of these

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

For two circles to have two common tangents, they must intersect at two distinct points. This occurs when the distance between their centers is less than the sum of their radii and greater than the absolute difference of their radii.