(n.) a group of neighborhoods in the Los Angeles area that are extravagantly wealthy and in relatively close proximity to Downtown LA. The Platinum Triangle consists of the Los Angeles districts of Bel Air and Holmby Hills and the independent city of Beverly Hills.
Other neighborhoods of Los Angeles and nearby towns (i.e. Pacific Palisades, Malibu, San Marino) are as wealthy as those in the Platinum Triangle but are not considered part of this grouping because they are not as close to the immediate Los Angeles area (Downtown LA).
The Platinum Triangle is home to several Hollywood celebrities as well as good restaurants and shopping, exemplified by Rodeo Drive in Beverly Hills.
Politically, the Platinum Triangle is left-of-center and tends to vote for Democratic candidates in local, state, and federal elections.
"-I'm so glad I transferred from UCLA to USC. All my new friends are so fabulous. I'm going to someone's house in Bel Air this weekend.
-Oh you're so lucky. I love the Platinum Triangle."