1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution I know how to solve B. Since the point C is on AB. [tex]Z_C=tZ_A+(1-t)Z_B[/tex], then since t is a function of [tex]Z_A[/tex], [tex]Z_B[/tex] and s, we can write Z_C as a function of those. However, I don't have a clue for part A. Triangle OAB and Oab are not similar. Please help. Thanks.