Explaining The Universe on Instagram: "A triangle is a three-sided polygon that is one of the most basic shapes in geometry. It has three sides, three angles, and three corners, or vertices. No matter the type, the sum of its interior angles is always 180 degrees. Triangles can be classified by their sides as equilateral, isosceles, or scalene, and by their angles as acute, right, or obtuse. They are important in mathematics, engineering, and design because of their strength and stability, which