A consultant hired to study the feasibility and desirability of a performing arts center at a new Pentagon City shopping mall in Arlington has told county officials to expect a loss of about $500,000 annually in at least the first decade of its operation.

The report from the McLean-based Economic Research Associates notes that there is no lack of performing arts centers in the Washington metropolitan area but adds that there is still a demand for a 1,200-seat theater with a schedule of about 170 performances annually such as Arlington is considering.

The county paid $43,000 for the study after the developer of a planned Pentagon City hotel and shopping mall offered to contribute $5 million toward the construction of such a center at the mall or elsewhere in the county. The center is expected to cost about $5.7 million.

The County Board is expected to vote within two months on whether to accept the developer's offer.

In addition to the consultant's study, the county has asked for a staff analysis of costs and a study of how similar-sized communities have fared with arts centers.

"I don't know to what extent any municipally run cultural center around the country is not subsidized," said Ron Carlee, the county staff member spearheading the county study.

Carlee said preliminary studies show the county would have to pick up about $228,000 in operating costs annually, plus $300,000 in capital costs, for a total subsidy of 18 percent annually.

The proposed center "would make Arlington more of a total community than a suburban bedroom community," he said.

Mark Jinks, the county's budget chief, noted that the Economic Research Associates report considered only revenues directly related to the center and did not include such possible sources as income from real estate taxes and sales taxes from restaurants that might be patronized by theater-goers.

County Board member Albert C. Eisenberg said he has several questions, including what inducements would be needed to attract a major production to Arlington.