Triangle
noun
When you have something with three angles, what shape is that? It's a triangle.
さんかく
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.
三角のクラッカーをかってきてください。
Please go buy triangle crackers.
今、三角かんけいになっちゃってるんだよね。
I am stuck in a love triangle now.
カナダ人はピカソにかなり刺激を受けたに違いない。四角い箱に、丸いピザ、三角のピザスライスがあちこちにある。
Canadians must have been inspired by Picasso quite a bit. Square boxes, round pizzas, and triangle pizza slices are everywhere.