Answer:
136°
Explanation:
The sum of the interior angles of a quadrilateral = 360°
Sum the given angles and equate to 360
x + x - 10 + x + 30 + 2x = 360 , simplify left side
5x + 20 = 360 ( subtract 20 from both sides )
5x = 340 ( divide both sides by 5 )
x = 68
Then
largest angle = 2x = 2 × 68 = 136°