As their spacecraft approached a distant moon, Nova and Luna received four navigation measurements for possible approach paths: 7/4, 1.68, 1.666..., and sqrt(3). The guidance computer required them to classify and order the values before selecting a route. Nova identified 7/4 as rational because it equals 1.75. Luna noted that 1.68 was rational because it terminates, while 1.666... was also rational because its decimal digits repeat. However, sqrt(3) was irrational because 3 is not a perfect square and its decimal expansion does not terminate or repeat. To compare the measurements, they used sqrt(3) as approximately 1.732 and placed the values in increasing order: 1.666..., 1.68, sqrt(3), 7/4. The navigation display showed that a safe approach required a measurement between 1.70 and 1.74. Only sqrt(3) fell inside that interval. Nova and Luna selected its corresponding path, and the spacecraft began a safe approach toward the moon.