In a forming operation, the plastic deformation of a steel specimen starts under plane stress condition, where the principal stresses are \(σ_1=200\ Mpa\) and \(σ_2 = 100\ Mpa\). If the steel specimen follows von-Mises yield criterion, then the uniaxial tensile yield strength (in Mpa) of this steel material is ____ . (Rounded off to 1 decimal place)