@prefix concept: <https://w3id.org/kmath/concept/> .
@prefix course: <https://w3id.org/kmath/course/> .
@prefix math: <https://w3id.org/kmath/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix review_status: <https://w3id.org/kmath/review_status/> .
@prefix scheme: <https://w3id.org/kmath/scheme/> .
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
@prefix textbook_section: <https://w3id.org/kmath/textbook_section/> .

concept:quadrilateral_area_by_diagonals a math:Concept ;
    rdfs:label "대각선을 이용한 사각형의 넓이"@ko ;
    skos:altLabel "사각형의 넓이"@ko ;
    skos:definition "두 대각선의 길이가 p, q이고 두 대각선이 이루는 각의 크기가 θ인 사각형의 넓이는 (1/2)pq sin θ이다. 평행사변형의 이웃한 두 변의 길이가 a, b이고 그 끼인각의 크기가 θ이면 넓이는 ab sin θ이다."@ko ;
    skos:editorialNote "2026-09-28 GRIP 대수 개념서와 시발점 워크북 대수가 독립된 학습 항목으로 다루는 것을 근거로 추가했다. 도메인 전문가 검토가 필요하다."@ko ;
    skos:inScheme scheme:concepts ;
    skos:prefLabel "area of a quadrilateral from its diagonals"@en,
        "대각선을 이용한 사각형의 넓이"@ko ;
    skos:topConceptOf scheme:concepts ;
    math:introducedIn course:algebra ;
    math:requires concept:triangle_area_by_sine ;
    math:requiresTransitively concept:angle,
        concept:circular_sector,
        concept:coordinate_plane,
        concept:direct_proportion,
        concept:function,
        concept:general_angle,
        concept:geometric_construction,
        concept:graph,
        concept:integer,
        concept:inverse_proportion,
        concept:parallel_line_property,
        concept:polygon_property,
        concept:positional_relation,
        concept:power,
        concept:pythagorean_theorem,
        concept:radian_measure,
        concept:rational_number,
        concept:similarity,
        concept:square_root,
        concept:triangle_area_by_sine,
        concept:triangle_congruence,
        concept:triangle_similarity,
        concept:trigonometric_function,
        concept:trigonometric_ratio ;
    math:reviewStatus review_status:needs_review ;
    math:sourceSection textbook_section:grip_algebra_07_09_quadrilateral_area,
        textbook_section:sibaljeom_workbook_algebra_theme22_triangle_area ;
    math:taughtIn course:algebra .