**Q: **Are Euler Angles three angles introduced by Leonhard Euler to describe the orientation of a rigid body? ¶

**A: **Yes.

**Q: **Are Euler Angles based on the axes of the above-mentioned reference frames and an additional axis called the line of nodes? ¶

**A: **Yes.

**Q: **Are Euler Angles also essential for basic theoretical work? ¶

**A: **Yes.

**Q: **Are Euler Angles directly measurable? ¶

**A: **Yes.

**Q: **Are Euler Angles a means of representing the spatial orientation of any reference frame by three angles? ¶

**A: **Yes.

**Q: **Are Euler Angles the transpose of that shown in the table above? ¶

**A: **Yes.

**Q: **Are Euler Angles defined as a sequence of rotations? ¶

**A: **Yes, and all the solutions can be valid, but there will be only one inside the angle ranges.

**Q: **Are Euler Angles also used extensively in the quantum mechanics of angular momentum? ¶

**A: **Yes.

**Q: **Are Euler Angles also used to describe the orientation of a frame of reference relative to another? ¶

**A: **Yes.

**Q: **Are Euler Angles one way to represent orientations? ¶

**A: **Yes.