The P is perimeter. help please this is a test!

3.4a=57.8 what is the the value of a

Match the following reasons with the statements given to create the proof. 1. do = ob, ao = oc sas 2. doc = aob given 3. triangle cod congruent to triangle aob vertical angles are equal. 4. 1 = 2, ab = dc if two sides = and ||, then a parallelogram. 5. ab||dc if alternate interior angles =, then lines parallel. 6. abcd is a parallelogram cpcte

What is a correct first step in solving the inequality-4(3-5x)> -6x+9