D because perpendicular lines intersect at a right angle and D is the only shape with right angles.
This is how you add fractions..
I have solved it step-by-step. If you understand this, you'll know how to subtract, too.
If you don't understand, message me :)
Answer:
x = 30
Step-by-step explanation:
4x + 2x = 180
6x = 180
x = 30