A 13-year-old boy jumped to his death from the balcony of his high-rise apartment in the Bronx Monday after he was sent home from school for not paying attention, family members said.

Juda Agyemang fell 21 floors and landed in front of the Tracy Towers on Mosholu Parkway shortly after 5 p.m.

Family and friends gathered in the apartment last night, weeping, praying, and struggling to understand what happened to the promising youngster who had just taken the exam for the Bronx High School of Science.

"He was a brilliant boy," Juda's aunt, Mary Boakye, said. "He was a good basketball player, too."

They said Juda had a problem yesterday in an after-school academic program at Our Lady of Angels school on Sedgwick Ave. that got him sent home early for not paying attention.

"His mother met him downstairs," the aunt said. "He told her that he just wanted to go out and play basketball.

"She said yes but he had to eat first. She went to the kitchen to get her son food when she heard a noise from the balcony and he wasn't there anymore," the aunt said.

Juda's meal of soup and rice was still on the kitchen stove late Monday night.