ART

New York’s Whitney Museum of American Art, responding to protests by neighborhood and civic groups over a plan to build a 10-story addition to its building at Madison Avenue and 75th Street, announced a revised plan Tuesday that calls for reducing the proposed addition by nearly a quarter. The revision dramatically reduces the top structure in size--by more than half--and is substantially plainer. Yet exhibit space will increase to 54,700 square feet from its current 23,100 square feet--at an estimated cost of $37.5 million.