The figure depicts a simplistic optical fiber: a plastic core (n_1 = 1.58) is surrounded by a plastic sheath (n_2 = 1.44). A light ray is incident on one end of the fiber at angle theta. The rays is to undergo total internal reflection at point A, where it encounters the core-sheath boundary. (Thus there is no loss of light through that boundary.) What is the maximum value of theta that allows total internal reflection at A?