直角三角形`勾股定理`面积(国外英文资料).docVIP

直角三角形`勾股定理`面积(国外英文资料) Collected by oneself Mistakes are unavoidable For reference only In case of error Please correct me! Thanks A right triangle, and the area of the Pythagorean theorem Knowledge test point: Understand the judgment and property of right triangle Understand the angular relations of right triangles Master the use of some simple Pythagorean theorem of practical problems Its properties are widely used in line segment calculation, proving the relation of line segments, proving the square relation of line segments and the problems related to area Classic examples: [case 1] as shown In quadrilateral ABCD / A = 600 / B / D = = 900 BC = 2 CD = 3 Then AB =? Analysis: through the auxiliary line The quadrilateral problem is transformed into a triangle problem Is the key to inner division or outward complement? Answer： [case 2] as shown P is a point on the edge of ABC BC PC = 2PB Known / ABC = 450 / APC = 600 For angle ACB degrees Analysis: This is not simply by the angle of relationship between the launch angle ACB degrees And should use conditions of PC = 2PB and APC = 600 / to construct a right triangle with 300 angle This is the key to solving the problem Answer: / ACB = 750 (hint: C for CQ AP in the Q group Link BQ Then AQ = BQ = CQ) Exploration and innovation: [problem one] as shown Highway MN and highway PQ meet at point P And / QPN = 300 There is a middle school at A AP = 160 meters Suppose the car is moving Around 100 meters or less will be affected by noise Then the car runs along the PN direction on the highway MN Is the school affected by noise? If affected The speed of a car is known to be 18 kilometers per hour How many seconds does the school affect? Analysis: from school (A points) from the highway (MN) nearest distance (AD = 80 meters) start Within the range of 100 meters from the point A Using graphics According to the Pythagorean theorem and vertical theorem to solve it Solution: AD group MN slightly to D In the Rt ADP Delta We know that AD