The context is construction of three circles with different radii so that they touch each other externally using a graduated ruler and a compass.
I have done it by drawing a triangle where each side is the sum of the radii of distinct combination of two circles and then drawing the circles by taking the vertex as the centre of a circle.
My question is why does my method work and is this the standard method to do the construction in context because i could not find anything about it on the internet.