Two circles of radii 5 cm and 3 cm touch each other at P and also touch a line at Q and R.Length of QR is?

• ans: root(60)
  
  QR is actually the perpendicular distance from the center of the smaller circle to the radius of bigger circle.
  length of QR = root((3+5)^2 - (5-3)^2) = root(8^2 - 2^2) = root(64-4) = root(60)
• 11 years agoHelpfull: Yes(18) No(13)
• FOR POQ PQ=sqrt(5^2+5^2)=5root2
  for 3root2
  for triangle prq sqrt(18^2+50^2)=root68
• 11 years agoHelpfull: Yes(7) No(3)
• According the question the two circle will just ouch each other at point P
  and the line will be a common tangent touching the two circles at the point P and Q respectively
  So, by drawing another line which would be formed by joining diameters of the two circle and intersecting the tangent at a point outside the two circle, touching the two circle at point A and B(line would be APB).
  
  now we can easily use the tangent property which is QR^2=(5+5)x(3+3)=root(60)
• 11 years agoHelpfull: Yes(1) No(1)
• http://www.ilovemaths.com/2circle.asp
• 10 years agoHelpfull: Yes(1) No(1)
• ans : 16 cm
  two circle touch at point p and touch a line(q,r) passing trough the point p as its center....
  
  
• 11 years agoHelpfull: Yes(0) No(4)
• 4*root(3)
  
• 11 years agoHelpfull: Yes(0) No(0)