Question

If ABC and DEF are two triangles and AB/DE=BC/FD, then the two triangles are similar if
​

Answer 1

For example, if triangles ABC and DEF are similar, then angle pairs AB and DE, BC and EF, and CA and FE are all equal. Also, AB/DE=BC/EF=CA/FD. If these three ratios are equal, then the corresponding sides are said to be proportional.