D.C. Schools Chancellor Kaya Henderson announced a plan Wednesday to invest $20 million in new support programs for black and Latino male students in the District, including opening an all-boys college preparatory high school east of the Anacostia River.Henderson said her decision to invest heavily in the specific needs of boys of color has everything to do with “mathematics.” Black and Latino boys make up 43 percent of the students enrolled in D.C. public schools. By almost any measure — reading and math scores, attendance and graduation rates — their performance is lagging.