Given the stress element C (the element is just bigger than a point!), I have drawn the Mohr's stress circle using the normal and shear stress combinations on the x and y faces of the element. Note that point A on the circle corresponds to the stresses on the y face in element Co.

Label the stress coordinates (σ,τ) for each of the points B, C, D, and E. Estimate the coordinate stress values from the circle, and indicate where the maximum and minimum normal stresses (principal stresses) and the maximum and minimum shear stresses occur.