noun, noun which may take the genitive case particle 'no'
Refers to the geometric shape; also used attributively with の to mean 'triangular'.
三角形の内角の和は180度です。
The sum of the interior angles of a triangle is 180 degrees.
机の上に三角形の紙が置いてある。
A triangular piece of paper is on the desk.
This roof has a triangular shape.
Please find the area of this triangle.
I cut the sandwich into triangles.
I drew a triangle on the paper.
equiangular triangle; equilateral triangle; regular triangle
equilateral triangle