# The angle between two planes

**The angle between two planes (Question)**

For two given planes, find the angle between them.

- Plane 1 = r.(3i + 5j – 1) = 2
- Plane 2 = r.(2i + j – k) = 5

*Guide: *

*cos x = (Unit vector of x1)*(Unit vector of x2)*

**The angle between two planes (Answer)**

- 46.36

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