Although millions of Americans watched Florence Griffith Joyner win the gold in the 100-meter dash at the Seoul Olympics, few of those watching could have translated those meters into yards. (It's 109.36 yards.)

Thirteen years after the Metric Conversion Act of 1976 went into effect, a majority of the American public still does not know - or care to know - about the almost universally accepted system of measurements. Instead, we rely on the archaic British imperial system - a system even the British are giving up.America's love-hate relationship with the metric system has been going on since the country's founding. Both Thomas Jefferson and John Quincy Adams saw in the newly developed metric system - it was invented in the 1790s - a method that was both simple and effective. But those in government with a less visionary bent blocked both efforts.

Although a bill in 1866 legally sanctioned the metric system, little else was done toward the metric conversion of America until 1968, when the Department of Commerce was asked to study the metric system. The three-year study concluded that with the increasing metrifica-tion of the world's industrialized nations, America should follow suit, and in 1975 the Metric Conversion Act went into effect.

With the passage of the 1975 act, many people thought that America was finally on its way to adoption of the metric standard. But Jim McCracken of the Commerce Department's Office of Metric Programs says that even though the 1975 act stressed voluntary conversion, many people and organizations put a 10-year limit on its acceptance. In 1982, President Reagan dissolved the U.S. Metric Board as part of his efforts to streamline the government, and by 1985, metric conversion efforts had reached what McCracken calls their nadir.

Although McCracken says there was "a slow erosion over the last five to eight years away from U.S. focus on metric conversion," he sees the tide moving once again toward met-rification. A recent section in the 1988 trade bill states that "industry in the United States is often at a competitive disadvantage when dealing in international markets because of its non-standard measurement system . . . " The bill goes on to designate the metric system as the "preferred system of weights and measures for the United States trade and commerce" and requires each federal agency by fiscal 1992's end - the same year the European Community will open its trade borders - to have adopted the metric system, if economically feasible.

With the federal government moving toward metrification, both McCracken and Bob Peterson, director of development for the American National Metric Council, see American business going the same way. Already, according to Peterson, almost 98 percent of all new American cars are metric.

To help promote metrification, the National Council of Teachers of Mathematics sponsored National Metric Week, Oct. 9-15. While McCracken and Peterson are both cautiously optimistic about American metrification, both agree that Americans will never become a totally metric society. By the 1992 Summer Olympics Americans might be talking about the 100-meter dash, but they're unlikely to say of an outfielder's errant throw to home plate, "He missed it by a kilometer."