Medians and Altitudes of Triangles Concept 37 Median

Medians and Altitudes of Triangles Concept 37

• Median – a segment that connects the vertex of the triangle to the midpoint of the opposite side of the triangle.

• Median of a Triangle – Medians do have one vertex as an endpoint. – Centroid – the point at which medians meet at one point. – Where is the centroid located? • Always inside the triangle.

Medians of a Triangle Theorem

Example 1 The medians of ABC meet at centroid, point D. Find the indicated values. Find BG =12 Find BD = 8

Example 2 G is the centroid of ABC, AD = 15, CG = 13, and AD CB. Find the length of each segment. a. AG = 10 b. GD = 5 c. CD = e. GB = 13 d. GE = 6. 5 f. Find the perimeter of ABC

3. In ΔXYZ, P is the centroid and YV = 12. Find YP and PV.

4. In ΔABC, CG = 4. Find GE.

Find the centroid of the given triangle. Find the midpoint D of BC. Graph point D.

• Altitude – a segment from a vertex that is perpendicular to the opposite side or to the line containing the opposite side.

Altitudes of a Triangle – Altitudes have one vertex as an endpoint. – Orthocenter – the point at which altitudes meet at one point. – Where is the orthocenter located? • Acute Triangle – Inside triangle • Right Triangle – On the vertex of the right angle • Obtuse Triangle – Outside, behind the obtuse angle

Altitudes of a Triangle Theorem

6. COORDINATE GEOMETRY The vertices of ΔHIJ are H(1, 2), I(– 3, – 3), and J(– 5, 1). Find the coordinates of the orthocenter of ΔHIJ. Orthocenter Altitude through point I. Opposite reciprocal: Altitude through point J. Opposite reciprocal: Altitude through point H. Opposite reciprocal:

7. COORDINATE GEOMETRY The vertices of ΔABC are A(– 2, 2), B(4, 4), and C(1, – 2). Find the coordinates of the orthocenter of ΔABC. A. (1, 0) B. (0, 1) C. (– 1, 1) D. (0, 0)

Perpendicular Bisector Angle Bisector Cir cum circumcenter cen Inc ter incenter ent er centroid Median Altitude Ce ntro Ort hoc id ent er orthocenter