If p₁ and p₂ are mutually perpendicular principal stresses acting on a soil mass, the normal stress on any plane inclined at angle θ° to the principal plane carrying the principal stress p₁, is:#

• A. [(p‚Äö√á√Ö - p‚Äö√á√á)/2] + [(p‚Äö√á√Ö + p‚Äö√á√á)/2] sin 2≈í‚àè
• B. [(p‚Äö√á√Ö - p‚Äö√á√á)/2] + [(p‚Äö√á√Ö + p‚Äö√á√á)/2] cos 2≈í‚àè
• C. [(p‚Äö√á√Ö + p‚Äö√á√á)/2] + [(p‚Äö√á√Ö - p‚Äö√á√á)/2] cos 2≈í‚àè
• D. [(p‚Äö√á√Ö + p‚Äö√á√á)/2] + [(p‚Äö√á√Ö - p‚Äö√á√á)/2] sin 2≈í‚àè