Answer:
136°
Step-by-step explanation:
In quadrilateral ABCD,
[tex]m\angle A = 180\degree - 107\degree = 73\degree[/tex](Angles in linear pair)
[tex]m\angle B = 61\degree [/tex](Vertical Angles)
[tex]m\angle C= 90\degree [/tex](Given)
[tex]m\angle A +m\angle B+m\angle C+m\angle D= 360\degree[/tex](Interior angle sum postulate of a quadrilateral)
[tex]73\degree +61\degree+90\degree+x= 360\degree[/tex]
[tex]224\degree+x= 360\degree[/tex]
[tex]x= 360\degree-224\degree[/tex]
[tex]x= 136\degree[/tex]
