At a point in a structure, there are two mutually perpendicular tensile stresses of 800 N/cm2 and 400 N/cm2. If the Poisson's ratio is 0.25, what would be the equivalent stress in simple tension according to maximum principal strain theory?
1
1200 N/cm2
2
400 N/cm2
3
900 N/cm2
4
700 N/cm2