Answer:
-0.5
Step-by-step explanation:
1/2 = 0.5
0.5 - 1 = - 0.5
The answer to your question is B.Opposite sides are parallel.
The triangles are isosceles. The following notation are for the angles. For example ABD is refer to the angle located in the B vertex, formed by the segments AB and BD.


Then

468=40x+18(x-3)
468=40x+18x-54
468=58x-54
522=58x
9=x
I'm not sure if you need to know x at all, if not, the top equation is all you need.