Answer:
B
Step-by-step explanation:
Finding the area of the trapezoid using the lengths in the diagram, we get (c)(2d+a+b)/2.
This is equal to c(d+b), so:
(1/2)(c)(2d+a+b)=c(d+b)
(1/2)(2d+a+b)=d+b
d+0.5a+0.5b=d+b
0.5a+0.5b=b
0.5a=0.5b
a=b
