DSE數學--方程式/定理(theorem)列表 Trigonometry
DSE數學--方程式/定理(theorem)列表 Trigonometry 1. General theorem Pyth. thm . ( Pythagorean Theorem ) The sum of the squares of the legs of a right triangle equals the square of its hypotenus e Converse of Pyth. thm IF the sum of the square of the length of two sides is equal to the square of the length of remaining side, the triangle is a right-angled triangle in which a right angled is located between the "two sides" ∠ sum of ∆ The sum of interior angles of triangle is equal to 180° ext. ∠ of ∆ An exterior angle of a triangle is equal to the sum of two non-adjacent interior angles of the triangle. base ∠s, isos. ∆ The base angles of an isosceles triangle are equal. sides opp. eq.∠s When two of the interior angles of a triangle are equal, the sides opposite to those interior angles are equal(i.e. form a isosceles triangle) greater ∠, greater side greater side, greater ∠ 2. Similar/congruent triangle Prove similar triangle: AA / three sides proportional / ratio of 2 sides, in
