Prismatic Reflection

The woods grow sparse until you find yourself before a jagged maw in the earth. Inside, light shatters against crystal walls. A narrow shaft of brilliance enters at an angle, bouncing from face to face like a restless spirit. The caverns hum, demanding you measure the light’s journey.


Question:
A light beam enters a crystal at 45°. It reflects off three internal surfaces before exiting. If each reflection follows the law of reflection, what is the total angle turned by the beam? (Answer in degrees)