Given:
A pentagon with one of the angle measuring 120°
To find:
The measure of rest of the angles (2x,3x,4x&5x)
Solution:
We know that the measure of  sum of all the angles in a pentagon = 540°
.°.
- 120°+2x+3x+4x+5x = 540°
 - 120°+14x= 540°
 - 120°-120°+14x = 540°-120°
 - 14x = 420°
 - x = 420°/14
 - x=30
 
.°.
2x

3x

4x

5x

Hope it helps
-------☆゚.・。゚ᵴɒƙυᴚᴀ_ƨȶäᴎ❀