[填空题]
Two polarizers are ori hzz7 v79f)w1.npmklh.g1 evaent 6ztlwly2tli -)k5lg- ed at 40$^{\circ}\,$ to each other and plane-polarized light is incident on them. If only 15% of the light gets through both of them, what was the initial polarization direction of the incident light? $^{\circ}\,$
