Lesson Subject: MEDIAN, BISECTOR AND HEIGHT TRIANGLE The goals of the lesson: introduce the concept of perpendicular, median, bisector and altitude triangle, learn how to build these segments
Lesson Plan № Step lesson The content of the lesson. 1 Organizing time Configure students on productive activities. 1 -2 2 Oral work Update of reference knowledge. 3 -4 3 Study of new material Define the height, bisector, medians of a : triangle. To acquaint students with the methods of building height, bisector, medians of a triangle. 10 4 Practical exercises and training exercises To form skills of building height, bisector, medians of a triangle. To be able to solve problems on construction. 9 -10 5 Independent work According to the textbook 6 Summing up the results of the Synthesize information obtained in class lesson 3 -4 7 Message homework 2 -3 Explain the content and the method of solving homework Time (Min) 10
Oral work - What is called the triangle? - What are the elements of the triangle you know and how much they had? - What are all the types of the triangle, you know?
Point M - the midpoint of AC В Point B - top Δ ABC Cut BM - the median Δ ABC MEDIAN - Е This segment, Р connecting the top triangle with the middle opposite sides А М С
Point B - top Δ ABC, В Segment BK - bisector of ABC Δ BISECTOR triangle - а segment bisector angle of the triangle, connecting the top triangle with the point the opposite hand А S E К С
Point B - top Δ ABC В Point H - perpendicular base Cut BH - height Δ ABC HEIGHT it is perpendicular, conducted by from the top triangle to direct, containing the opposite side К Р А Н С
AH segment - perpendicular to the line Point H - perpendicular base PERPENDICULAR- а line segment, perpendicular to a given line A H m
А Е С В
К Е В А Н С
В А М К Н ВМ – median Δ АВС ВК – bisector Δ АВС ВН – height Δ АВС С
Geometric marathon a) Perpendicular lines b) Triangle c) Vertical angles d) Obtuse angle f) Ray g) Cut h) Acute angle i) Point j) Extended angle k) Adjacent angles l) The right angle m) Bisector n) Direct
Check yourself: g , I , k , l , f , d , j , b, , n , m , c, a.
§Control of mastering new material
2) 6) 1) 8) 3) 7) 4) 9) 11) 5) 13) 10) 12) Number 1. Record number of triangles, conducted in which a) height, b) the median, c) the bisector. 14)
А В D F В A C № 2. In the triangle ABD is the median length of AF. Compare the length of the BF and FD segments. Answer: a) BF> FD; b) BF <FD; a) BF = FD. № 3. In the triangle ABC is the height of the segment BD. Determine the relative position of the lines BD and AC. Answer: a) BD perpendicular to AC; b) BD is parallel to AC; a) BD and AC intersect at an acute angle. D D G A В № 4. In triangle ABC, the segment BD bisects. Compare the measure-degree angles ABG and GBD. Answer: а) б) в)
lesson Summary Homework: § п. 25 № 19. § Вопросы № 8 - 10
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lesson 3 MEDIAN .......ppt