90 likes | 238 Vues
Beyond CPCTC. Lesson 3.4. Medians : Every triangle has 3 medians A median is a line segment drawn from any vertex to the midpoint of its opposite side. A median bisects the segment. B. E. F. A. C. D. Name the 3 medians of triangle ABC. BD CF AE. Altitudes :
E N D
Beyond CPCTC Lesson 3.4
Medians: Every triangle has 3 medians A median is a line segment drawn from any vertex to the midpoint of its opposite side. A median bisects the segment.
B E F A C D • Name the 3 medians of triangle ABC. • BD • CF • AE
Altitudes: Every triangle has 3 altitudes. An altitude is a line segment drawn perpendicular from any vertex to its opposite side. *The altitude could be drawn outside the triangle to be perpendicular. Altitudes form right angles 90˚ You may need to use auxiliary lines (lines added)
AD & BE are altitudes of ABC. AC & CD are altitudes of ABC. BD & AE are altitudes of ABC A D C B E
Could an altitude also be a median? Yes, for an isosceles triangle when drawn from the vertex.
MidSegments • A midsegment of a triangle is a segment that connects the midpoints of two sides of a triangle. • The midsegment is parallel to the third side and is half it’s length.
Postulate: Two points determine a line, ray or segment. Determine (one and only one line)
Given • An altitude of a forms rt. s with the side to which it is drawn. • Same as #2 • If s are rt. s, they are . • Reflexive Property. • Given • ASA (4, 5, 6) • CPCTC • Subtraction Property (6 from 8) • CD & BE are altitudes of ABC. • ADC is a rt. . • AEB is a rt. . • ADC AEB • A A • AD AE • ADC AEB • AB AC • DB EC