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5.3: Concurrent Lines, Medians and Altitudes. Objectives : Students will be able to… Identify properties of perpendicular bisectors and angle bisectors Identify properties of medians and altitudes of triangles. Vocabulary. Concurrent: 3 or more lines intersect at a point
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5.3: Concurrent Lines, Medians and Altitudes Objectives: Students will be able to… Identify properties of perpendicular bisectors and angle bisectors Identify properties of medians and altitudes of triangles
Vocabulary Concurrent: 3 or more lines intersect at a point Point of Concurrency: where the lines intersect
Median of a Triangle A segment whose endpoints are a vertex of a triangle and the midpoint of the opposite side
Additional Info about Circumcenters: • If you were to draw a circle around a triangle, where each vertex of the triangle are points on the circle, the circle would be circumscribed about that triangle • The circumcenter of the triangle is ALSO the center of the circle circumscribed about it
Perpendicular Bisectors Acute triangle: Circumcenter inside triangle Right triangle: Circumcenter lies ON the triangle Obtuse Triangle: Circumcenter is outside triangle
Find the center of the circle that you can circumscribe about the triangle with vertices (0, 0), (-8,0) and (0,6). • Plot the points on a coordinate plane. • Draw the triangle • Draw the perpendicular bisectors of at least 2 sides. • The circumcenter of this triangle will be the center of the circle.
Incenters A circle is inscribed in a triangle when the circle is tangent to each side (also called an incircle) The incenter of a triangle is the center of an inscribed circle
Additional Info about incenters: • The incenter of ALL types of triangles is always INSIDE the triangle.
WHAT IS THE DIFFERENCE BETWEEN A MEDIAN AND A PERPENDICULAR BISECTOR??
CENTROIDS G is the centroid AG = AD BG = BF CG= CE
O is the centroid of triangle ABC. CE = 11 FO = 10 CO = 8 Find EB. Find OD. Find FB. Find CD. If AO = 6, find OE.
Altitude of a Triangle The perpendicular segment from the vertex to the line containing the opposite side Obtuse Triangle: Outside Acute Triangle: Inside Right Triangle: Side
What is the difference between an altitude and a perpendicular bisector?