1. To find a radian measure of any angle by its given degree measure it is necessary to multiply: a number of degrees by / 180 ? 0.017453, a number of minutes – by / (180 · 60 ) ? 0.000291, a number of seconds – by / (180 · 60 · 60 ) ? 0.000005 and to add the found products.

Example: Find a radian measure of an angle 12° 30’ with an of the fourth accuracy decimal place.

Solution: 2. To find a degree measure of any angle by its given radian measure it is necessary to multiply a number of radians by 180° / ? 57°.296 = 57°17’45” ( a relative error of the result will be ~ 0.0004%, that corresponds to an absolute error ~ 5” for a round angle 360° ).

Example: Find a degree measure of an angle 1.4 rad. with an accuracy up to 1’.

Solution: