A strain gauge rosette was applied at a point on the free surface of a loaded structural member and resultantly developed the state of strain on an element with components ?x = 900?, ?y = 400?, ?xy = 500?. If the material for the structural member has a modulus of elasticity of E = 207 GNm-2 and Poisson’s ratio ? = 0.3, determine:

(a) The principal strains ?1, ?2, ?3 and the maximum in-plane shear strain.