In the given figure, PA and PB are tangents to the circle at A and B respectively and the chord BC is parallel to tangent PA. If AC = 6 cm, and length of the tangent AP is 9 cm, then what is the length of the chord BC?

• ans:4
  
  PA = PB = 9 cm ( Length of tangents from an external point)
  
  Angle PAB = Angle ABC ( alternate angles PA !! BC)
  
  AC = AB = 6 cm
  
  Triangles PAB and ACB are Isoscelles and sre similar triangles
  
  ( They are equiangular)
  
  Taking the ratios of respective sides
  
  BC/AB = AC/PB
  
  BC/6 = 6/9
  
  BC = 4 cm
• 11 years agoHelpfull: Yes(2) No(3)