In parallelogram abcd, the measure of angle a=55°,line segment ab=2.5 feet and line segment bc =1 foot. find the measure of angle c.

It is better to illustrate the problem. As you can see on the figure, angle A and angle C are opposite angles. First, we define parallelogram. Parallelogram is a quadrilateral with two sets of parallel sides. Moreover, the opposite sides and the opposite angles are equal. 

From the definition alone, there is no need to solve. Angle C = Angle A = 55 °.