The stress normal to the plane is slightly tensional. We have a large compressional stress at a grazing angle to the plane and a weak tension at a steep angle, so it's not intuitively obvious what the result will be. It has to be read off the diagram. If there is stress in only one direction and zero stress in the perpendicular direction, the condition is called uniaxial stress. Uniaxial stress is handled just like any other stress situation.
Measure angles with respect to the pole of the plane.
Below, we plot the Mohr Circle. The minimum stress is zero so the circle passes through the origin. Measure angles in the Mohr Circle just like any other situation. Finally, read off the stresses. Since we have a stress acting along the plane and no other stress counteracting it, there is a shear stress.