A cylindrical specimen of a metal alloy 48.8 mm long and 9.09 mm in diameter is stressed in tension. A true stress of 327 MPa causes the specimen to plastically elongate to a length of 55.0 mm. If it is known that the strain-hardening exponent for this alloy is 0.3, calculate the true stress (in MPa) necessary to plastically elongate a specimen of this same material from a length of 48.8 mm to a length of 57.6 mm