Since you have the triangular face, you need to wear the sunglasses with round shape lenses to make the face with pointed corner look cute and round. You could choose the ray ban sunglasses with round lenses. The ray ban sunglasses are good at the perfect quality which will make you wear for many years and coo design which will make you look fashionable.
Triangle shape face is featured with narrow forehead and eyeliner and wider cheek and chin. To look best, you need semi-rimless sunglasses which attracts more attention for your upper face and distract attentions from your wide cheek. Top heavy style sunglasses do well in balancing out the broadness of the chin.
Triangular face should wear sunglasses whose frame color is light. Because triangular face is similar to square face, for example, both faces have apparent cheek bones, less wide forehead. Faces of this kind shape loo shorter. So you can choose those sunglasses whose color changed gradually from the upper to lower layer.
Don't choose those whose frame color is too deep. Because deep color of the upper and the lower layer will make your face shape more clear.
So it is the best choice for you to choose the sunglasses whose lower side color is light, which makes your face more beautiful.