If you are talking about plane strain in elastic isotropic materials, you can find the answer in any solid mechanics reference. See the Analysis of Plane Strains.
Thank you, in this case I deal with sensor embedded in concrete slab which simulate as plate. Dr.Mohammed I can't take this value as general and I have already known that I have to consider Poisson's ratio as a major key.
If you mean Rosette strain gage, which evaluates the stain in 0 degree (x), 90 degree (y), and 45 degree.....then the strains in x and y directions are already calculated (if the sensor is oriented well)...and from these strains you can calculate the shearing strain or the normal strain at any angle using defined formulas that can be found easily in ant Solid Mechanics or Strength of Material Book.