In geometry, the side opposite a given angle (for example, the side opposite an angle in a triangle).
この三角形の∠Aに対する対辺の長さを求めよ。
Find the length of the side opposite angle ∠A in this triangle.
対辺と角の関係を使って解く問題がよく出る。
Problems using the relationship between an opposite side and its angle often appear.