# 9
An ant lives on the surface of a regular tetrahedron with edges of length 5cm. It is currently at the midpoint of one of the edges and has to travel to the midpoint of the opposite edge. What is the length (in cm) of the shortest route to the destination assuming the ant can only travel along the surface of the tetrahedron? (Note: 2 edges in a tetrahedron are said to be opposite if they don't share any endpoints).

2.5*√3
2.5*(1 + √3)
7.5
5
2.5*√2

• The answer is 5, and here is the explanation
  
  But first lets see what a regular tetrahedron is:- It has four equilateral triangles, one at the base and other three stand on the edges of the base triangle and meet each other at the top.
  See this to clear confusions:- http://www.youtube.com/watch?v=Aro-_wFUpFo
  
  Since the ant is at the midpoint of one edge and it want to go to midpoint of another edge it has to travel :
  (From midpoint of source edge to the common vertex) + (from common vertex to midpoint of destination edge)
  
  2.5 + 2.5 = 5 cm Ans
• 11 years agoHelpfull: Yes(11) No(2)
• ans is 5
  because the surface of the tetrahedron is a square so opposite edge midpoint is away 5cm from initial edge mid point.it means distance between two opposite edge=length of edge in tetrahedron at base of tetrahedron.
• 11 years agoHelpfull: Yes(6) No(5)
• (2.5+2.5) = 5cm
• 11 years agoHelpfull: Yes(2) No(1)
• as it is gven in that opposite do not have the common point . How the solution came to be 5. I suppose it will be 7.5
• 11 years agoHelpfull: Yes(2) No(1)
• i thnk it is 10 cm.as the edges shld not hv any common end point so the ant has to travel=2.5+5+2.5 cm=10cm
• 11 years agoHelpfull: Yes(1) No(0)
• Answer is 2.5(1 + sqrt3)
• 10 years agoHelpfull: Yes(0) No(0)