This handrail is made from congruent parallelograms. in parallelogram abcd, ab = 17.5 , de = 18, and angle bcd is 110º. find the measure of angle abc.

I'm a bit confused however this is what I have come up with. I did not use the values for AB or DE at all. As a warning, my geometry skills are not great as I do not remember much from 8th grade. 
If my memory serves me right, angle BCD's degree must equal's angle DAB's degree, so 110. A parallelogram's angle sums up to 360. If you add BCD and DAB's measurements, it equals 220, subtract this number from 360 and you get 140. angles ABC and ADC must also equal one another so if we divide 140 we get the individual angle degrees. If you do this you should get 70 degrees.