A 60o strain rosette, or delta rosette, consists of three electrical-resistance strain gages arranged as shown in

Question:

A 60o strain rosette, or delta rosette, consists of three electrical-resistance strain gages arranged as shown in the figure. Gage A measures the normal strain (a in the direction of the axis. Gages B and C measure the strains and in the inclined directions shown.
Obtain the equations for the strains (x, (y, and (xy associated with the xy axis?