角
角についての五つの単元です。分度器での測り方、角の種類、和が90°や180°になる角の組、一本の直線が二本の平行線と交わってできる八つの角、三角形と多角形の内角の和を学びます。各ページの三角比ラボには、分度器、平行線の組、頂点をドラッグできる三角形があります。
進み具合
このコースの出典 (5)
- OpenStax, Contemporary Mathematics : 10.2 Angles (angle = two rays with a common endpoint, the vertex; naming ∠ABC and m∡; protractor use, centre mark on the vertex; acute < 90°, right 90°, obtuse between 90° and 180°, straight 180°; adjacent, supplementary (sum 180°), complementary (sum 90°), vertical angles equal; a transversal of two parallel lines makes eight angles numbered 1 to 8, alternate interior 3 and 6, 4 and 5, alternate exterior 2 and 7, 1 and 8, corresponding 1 and 5, 3 and 7, 2 and 6, 4 and 8: openstax.org/books/contemporary-mathematics/pages/10-2-angles)
- 10.3 Triangles (interior angles add to 180°; Thales is credited with the equal base angles of an isosceles triangle and with vertical angles being equal: .../pages/10-3-triangles)
- 10.4 Polygons, Perimeter, and Circumference (interior angle sum S = (n − 2)180°, heptagon 900°: .../pages/10-4-polygons-perimeter-and-circumference)
- OpenStax Precalculus 2e 5.1 Angles (one degree is 1/360 of a full rotation; radian: openstax.org/books/precalculus-2e/pages/5-1-angles)
- MacTutor History of Mathematics, University of St Andrews, "The trigonometric functions" (Ptolemy divides the circle into 360° showing Babylonian influence; 30′ is half of 1°: mathshistory.st-andrews.ac.uk/HistTopics/Trigonometric_functions/)
確認日: 2026-10-17