The direction of 12 m is towards west north with an angle of 20 with the y-axis or north.
The direction of 20 m is towards the south west with an angle of 40 with the x-axis or west.
From the given figure,
The angle between the 12 m and the west is,
Thus, the angle between the 12 m and 20 m is,
The resultant of the 12 m walk and 20 m walk is,
Substituting the known values,
Thus, the magnitude of the resultant of R is 19.5 m.