What is the value of x ? (give reasons for all steps)

Hello there,
This is a regular polygon. To find the sum if its angle,
(n-2)180 (where n is the number of sides)
(4-2)180= 360 degrees
To find the unknown angle= 360-76-105-120
                                          = 59
Angle x= 180 - 59 (angles on a straight line)
           = 121 degrees
Hope this helps :))

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