By YANCEY ROY 

ALBANY — The Pythagorean theorem, a lesson learned in high school geometry, sank James Robbins' bid to overturn a conviction for selling drugs in a school zone.

New York's highest court yesterday upheld Robbins' conviction for selling drugs within 1,000 feet of a midtown Manhattan grade school. To do so, the Court of Appeals ruled that authorities were correct to measure the distance in the straightest possible line.

Robbins was arrested in March 2002, accused of selling crack to an undercover officer about three blocks from a Catholic school on 43rd Street. State law does not specify whether the distance from a school is to be measured "as the crow flies" or as a pedestrian would have to travel. Asking for a lighter sentence, Robbins argued that because "crows do not sell drugs," the pedestrian route should be the rule of thumb.

Because buildings stand in the way from the school to the arrest site on 40th Street, the shortest distance by foot is 1,091 feet. But the trial judge allowed prosecutors to use geometry, specifically a right triangle, to determine the distance. A detective measured the distance from 40th Street to 43rd Street, then from 43rd Street to the school, then applied the Pythagorean theorem to come up with the hypotenuse — or the shortest possible line from the school to Robbins. The cop's answer: 907 feet.

Robbins was convicted and sentenced to six to 12 years in state prison. The Court of Appeals upheld the conviction in a 7-0 decision.