When a figure has 4 sides, the sum of its angles will always be equal to 360 degrees. The image above can be represented by the following formula:
x + 103 + 122 + 58 = 360
Simplify the left side of the equation:
x + 283 = 360
Subtract 283 from both sides of the equation:
x + 283 ( – 283 ) = 360 ( – 283 )
x = 77
We have now proven that the value of “x” is equal to 77 degrees.
I hope this helps!