Identify the pattern and fill the blank

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?

Asmall business produces and sells balls. the fixed costs are $20 and each ball costs $4.32 to produce. each ball sells for $8.32. write the equations for the total cost, c, and the revenue, r, then use the graphing method to determine how many balls must be sold to break even.

Precalculus question, image attached.