want another clever little measurment? Ok say you have 2 odd size round pipes carrying a fluid be it gas or other....... and you want to replace it with one to carry the same amount............ measure the diameter across the pipes internally, draw a right angled triangle using the dimensions of the pipes on both 90 degrees angles of the right angled triangle.............. the long diagonal side of the triangle is the internal diameter of the pipe you need to replace the two
