Plane Angle

Q. Angle between the intersection of two planes is called:

1. Acute angle
2. Solid angle
3. Plane angle
4. Obtuse angle

Q. What is the approximate value of 1 radian in degree measure?

1. ${27}^o{5}^{\prime }$
2. ${57}^o{16}^{\prime }$
3. ${180}^o$
4. ${90}^o$

Q. Define a radian.