Brielle Biermann isn’t the only Biermann girl who slays in a bikini! Her younger sister Ariana proves she also knows how to work it in a chic two-piece from their mom Kim Zolciak’s swimwear line, Salty K.On Sunday, June 14, the 18-year-old posted a series of pics to her Instagram feed cuddling up with the family’s rescue dog, Sinn, wearing nothing more than a white Salty K bikini. The stringy design is the Boardwalk Bikini, which retails for $180 ($90 for each piece).