A plan by the city of New Carrollton to annex the so-called Metro triangle and two neighboring communities was approved overwhelmingly in a referendum yesterday.

The count was 570 for the annexation to 105 against as slightly fewer than half of the city's 1,410 eligible voters participated in the referendum.

The result clears the way for the City Council to approve the annexation -- which it is expected to do Thursday -- although the land takeover could be blocked either by a pending suit or by voters in the areas New Carrollton wants to take over.

The potentially tax-rich "golden triangle" that New Carrollton wants contains a new Metro subway station and an Amtrak Metroliner station and is slated to house a multimillion-dollar industrial, commercial hotel compex called Metro East. The triangle, plus the 282 homes in the communities of West Lanham and West Lanham Hills, would give New Carrollton an estimated $214,800 in added annual tax revenue in 1983 if anticipated development is carried out.

But the annexation proposal sparked bitter debate and at least one lawsuit since New Carrollton Mayor Jordan Harding announced it in August.

Businesses from Metro East have showered City Hall with letters of protest. Calling the proposal a greedy land grab, they contend that New Carrollton's move is a blatant attempt to cash in on what some developers say is "the hottest piece of property in town."

"We're getting nothing for something, and they're getting something for nothing," argued real estate broker James Rogers, who led the opposition from the Metro East business community. Because the complex has all new streets, Prince George's County police protection and its own commercial trash removal, annexation would mean paying taxes without receiving additional services, Rogers contends.

Annexation supporters from West Lanham and West Lanham Hills, who petitioned in October to become a part of New Carrollton, called the move "a protective godsend."

"In unity there is strength," said West Laham Hills Civic Association President Bronson Row. "With Metro here, many problems face us, and if we stand unincorporated we are as a lamb for the slaughter."

His view is not universally shared. "It's not over yet," said West Lanham resident Carole Tarbox after yesterday's vote. She said she plans to lead a petition drive that could lead to a referendum in her community aimed at blocking the annexation. "I do not think we need the extra layer of government because we have good services from the county," she said.

Only New Carrollton residents were elegible to vote in yesterday's referendum.

Although city officials have declined to list any services they will provide to the Metro East community, West Lanham and West Lanham Hills residents can expect at least 20 municial services, including zoning protections, beautification and refuse collection, and an average yearly tax savings of $32.90, according to City Administrator John Brunner.

Throughout the four-month tug-of-war over the choice property, Mayor Harding asserted that his interest is in protecting the city of New Carrollton.

"Annexation will give the City Council needed input and certain controls over an area that is going to impact very seriously on our community," said Harding, who is in his fifth term as mayor.

A lawsuit seeking to prevent the annexation was filed by three Metro East property owners, a New Carrollton resident and a West Lanham resident. It contends that the mayor and council made decisions at secret meetings and falsely labeled as legal fees $11,000 that actually was paid for a survey of the land proposed for annexation. Harding has vigorously denied those allegations and labeled them "unscrupulous."