A Thin Laser Beam Traveling in Air Strikes the Surface $41.2 ^ { \circ }$

Short Answer

A thin laser beam traveling in air strikes the surface of a glass plate at $41.2 ^ { \circ }$ with the normal. In the plate, this beam makes an angle of $22.4 ^ { \circ }$ with the normal. What is the speed of light in this glass? $\left( c = 3.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s } \right)$