Owners of The Triangle hired Washington, D.C.-based Madison Marquette Retail Services to handle leasing and management as a renovation takes hold at the Costa Mesa shopping center.

The Triangle, formerly known as Triangle Square, is owned by Newport Beach-based real estate investor Greenlaw Partners, Westbrook Partners LLC of New York and Walton Street Capital LLC of Chicago.

The nearly 200,000-square-foot retail center is set to see openings for Saddle Ranch Chop House, El Corazon and Olive Branch Pizza by the end of the year.

The restaurants are part of a new strategy for the center that focuses on a greater mix of dining and entertainment businesses.

The Triangle’s renovation, expected to be done by 2013, will include new landscaping, building facades and signage at the center.