Lesson 6-1 Medians
Ohio Content Standards:
Ohio Content Standards: Formally define geometric figures.
Ohio Content Standards: Formally define and explain key aspects of geometric figures, including: a. interior and exterior angles of polygons; b. segments related to triangles (median, altitude, midsegment); c. points of concurrency related to triangles (centroid, incenter, orthocenter, and circumcenter); d. circles (radius, diameter, chord, circumference, major arc, minor arc, sector, segment, inscribed angle).
Median
Median A segment that joins a vertex of the triangle and the midpoint of the side opposite that vertex.
Median A B D median BD C
A E B D C
A E B D C Find BE if AB = 18.
If CD = 2x + 5, BD = 4x – 1, and AE = 5x -2, find BE.
Centroid
The common point where the medians of a triangle intersect. Centroid The common point where the medians of a triangle intersect.
Centroid C A B D L E F centroid
Concurrent
When three or more lines or segments meet at the same point. Concurrent When three or more lines or segments meet at the same point.
Theorem 6-1
Theorem 6-1 The length of the segment from the vertex to the centroid is twice the length of the segment from the centroid to the midpoint.
Theorem 6-1 2x x
Y N P Q X M Z Find YQ if QM = 4.
Y N P Q X M Z If QZ = 18, what is ZN?
Assignment: Pgs. 231-233 8-18 all, 24-29 all