please help quickly

Mohr's circle is shown for a point in a physical object that is subjected to plane stress (i.e. z=0 ). (a) Determine the stresses x,y and xy and show them on a stress element. ( 2 pts) (b) Determine the principal normal stresses, the maximum inplane shear stress, and average normal stress acting at the point (you must show calculations) as well as the absolute maximum shear stress. (10 pts) (c) Show principal normal, average normal and maximum inplane shear stresses on an appropriate sketch. ( 3pts)