Estimate the theoretical fracture strength of a brittle material ifit is known that fracture occurs by the propagation of anelliptically shaped surface crack of length 0.2 mm(0.007874 in) and having a tip radius of curvature of3 × 10-3 mm (1.181 ×10-4 in), when a stress of 1080 MPa(156600 psi) is applied.