4.7, 10.3, and 5.1 - 5.3 Flashcards
Median of a triangle (DEF)
a segment from a vertex to the midpoint of the opposite side
Where does the median lie?
ALWAYS on the INSIDE of a triangle
Altitude of a triangle (DEF)
The perpendicular segment from a vertex to the line that contains the opposite side.
(Basically from a vertex and is perpendicular to the opp. side)
Where can an altitude lay?
inside or outside the triangle, since it has to be perpendicular to the opp. side, for obtuse and acute triangles it will be on the outside of the triangle
Perpendicular Bisector of a segment
A line that is perpendicular to the segment at it’s midpoint
If a point lies on the perpendicular bisector of a segment,
Then the point is equidistant from the endpoints of the segment. (HAS A CONVERSE)
Distance from a point to a line
the length of the perpendicular segment from the point to the line
If a point lies on the bisector of an angle,
Then the point is equidistant from the sides of the angle.
(HAS A CONVERSE)
Incenter theorem
The bisectors of the angles of a triangle intersect in a point that is equidistant from the three sides of the triangle
Circumcenter theorem
The perpendicular bisectors of the sides of a triangle intersect in a point that is equidistant from the three vertices of a triangle
Orthocenter theorem
The lines that contain the altitudes of a triangle intersect in a point
Centroid theorem
The medians of a triangle intersect at a point that is two-thirds of the distance from each vertex to the midpoint of the opposite side
Centroid theorem 2/3’s rule
Centroid is always located 2/3’s from the first part of a segment, and the end is located 1/3 from that same segment
Parallelogram
A quadrilateral w/ both pairs of opp. sides parallel
If a quadrilateral is a parallelogram (1)
Then the opp. sides are congruent