Program to Convert Radian to Degree

Before moving to the actual solution, let's try to find out what is a degree, a radian, and their relations.

Radian: The radian is the standard unit of angular measure, used in many areas of mathematics. The length of an arc of a unit circle is numerically equal to the measurement in radians of the angle that it subtends. One radian is just under 57.3 degrees.

Degree: A degree (in full, a degree of arc, arc degree, or arcdegree), usually denoted by ° (the degree symbol), is a measurement of a plane angle, defined so that a full rotation is 360 degrees.
The relation 2pi*rad = 360° can be derived using the formula for arc length. 

An arc of a circle with the same length as the radius of that circle subtends an angle of 1 radian. The circumference subtends an angle of 2pi radians. 

Therefore the formula is: 

degree = radian * (180/pi)
where, pi = 22/7

Examples:  

Input : radian = 20
Output : degree = 1145.4545454545455
Explanation: degree = 20 * (180/pi)

Input : radian = 5
Output : degree = 286.3636363636364
Explanation : degree = 5 * (180/pi)

Note: In this programs, we have taken the value of pi as 3.14159 to get standard result in all three languages.  

286.479

Time Complexity: O(1), as we are not using any loops.

Auxiliary Space: O(1), as we are not using any extra space.

Example :

The following program demonstrates toDegree() and toRadians().

120.0 degree is 2.0943951023931953 radians.
1.312 radians is 75.17206272116401 degrees.

Time Complexity: O(1), as it is using constant operations
Auxiliary Space: O(1), as it is using constant variables

Reference: 
https://en.wikipedia.org/wiki/Radian 
https://en.wikipedia.org/wiki/Degree_(angle)