COMPLEMENTARY is not a difficult word. It means to combine in such a way as to enhance or emphasize the qualities of two people or procedures. Even so, SAT test writers used COMPLEMENTARY in a carefully crafted vocabulary in context question. The passage described how scientists used seismic monitoring and orbital imaging to search for impact craters on the surface of Mars. The two techniques are COMPLEMENTARY because they work together. However, many students were tempted by REDUNDANT meaning an unnecessary duplication that exceeds what is necessary. Watch out for REDUNDANT. It has appeared as both a correct and an incorrect answer on recent test questions.
COMPLEMENTARY – to combine and wok together in such a way as to emphasize the qualities of two people or procedures.