Suppose there is a round duct which contains round pipes. The diameter of the pipe is 2 cm. The duct contains 3 similar pipes which fit exactly into it. Find the diameter of the duct?
a.) 4 b.) 5 c.) 6 d.)7

• imagine the figure as a big circle that comprises of three small circles having radius 1 cm. now as you draw figure u will find that all three circles touch each other and also the circumference of outer big circle.
  now when you join the centers of all inner 3 circle, a equilateral triangle of side 2 cm will be formed. now find the in radius of this triangle which will be 2/sqrt3. so the radius of outer circle will be ((2/sqrt3)+1). hence diameter will be 2*((2/sqrt3)+1). which will be the diameter of the required duct.
• 9 years agoHelpfull: Yes(14) No(5)
• I think a) 4
  
• 9 years agoHelpfull: Yes(3) No(0)
• SIDDHARTH PRAKASH SINGH answer is right but 2/sqrt3 is circum-radius not in-radius.
• 9 years agoHelpfull: Yes(2) No(0)
• Arun Sharma(Pg No-392,Q.No-40,LOD-1)
• 9 years agoHelpfull: Yes(0) No(6)
• sORRY REFER LOD-2
• 9 years agoHelpfull: Yes(0) No(8)