Please go buy triangle crackers.
I am stuck in a love triangle now.
Canadians must have been inspired by Picasso quite a bit. Square boxes, round pizzas, and triangle pizza slices are everywhere.
When you have something with three angles, what shape is that? It's a triangle.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.