I need a step by step explanation for these problems. The language itself is difficult for me to understand.

Problem Set 1 (1) This problem is another area computation using an \"in-and-out\" argument similar to the one found in the Nine Chapters for the gou-gu theorem. Consider the parallelogram in the plane with vertices as pictured in Figure 1 at the points (0,0), (11,5), (c, d), and (a + c, b + d) (the drawing implicitly assumes that if