8. In the figure below, ABC is a right triangle, a + b - 135 degrees, and c + d = 55 degrees. Find x.

Answer:
x=80 degrees
Step-by-step explanation:
We are given that
ABC is a right triangle
Therefore, angle B=90 degrees
Angle A=a+b=135 degrees
Angle C=c+d=55 degrees
Angle D=x
We have to find the value of x.
We know that
In quadrilateral
Sum of all angles of quadrilateral=360 degree
[tex]\angle A+\angle B+\angle C+\angle D=360^{\circ}[/tex]
[tex]135+90+55+x=360[/tex]
[tex]280+x=360[/tex]
[tex]x=360-280[/tex]
[tex]x=80[/tex]
x=80 degrees