postulates and theroms and stuff Flashcards
Postulates 1 (ruler postulate)
points in a line can be matched 1:1 with real numbers. The real number that corresponds to a the coordinate of the point
Postulate 2 (Segment Addition Postulate)
If B is between A & C, then AB + BC=AC
Postulate 4 (Angle Addition Postulate)
If point B lies in the interior of <AOC, then m<AOB + m<BOC = m<AOC. If <AOC is a straight angle and B is any point not on line AC, then m<AOB + m<BOC=180
Postulate 5
A line contains at least two points; a plane contains at least three points not all in one line; space contains at least 4 points not all in one plane
Postulate 6
Through any 2 points there is exactly one line
Postulate 7
Trough any three points there is at least one (infinite) plane, nd through any three noncollinear points there is exactly one plane (only one).
Postulate 8
If 2 points are in a plane, then the line that contains the points is in that plane
Postulate 9
If 2 planes intersect, the their intersection is a line
Theorem 1
If 2 lines intersect, then they intersect in exactly one point
Theorem 2
Through a line and a point not in the line there is exactly 1 plane (similar to 3 noncollinear points)
Theorem 3
If 2 lines intersect, then exactly 1 plane contains the lines
Midpoint of a segment def
point equidistant from the endpoints of a line segment
Bisector of a segment def
a figure that passes through the midpoint of a segment
Midpoint Theorem
If M is the midpoint of line AB, then AM is ½AB and MB ½AB
Angle Bisector Theorem
If BX if the bisector of <ABC, then m<ABC=½ m<ABC and m<XBC=½ m<ABC
Vertical angles theorem
Vertical angles are congruent
2 lines are perpendicular, then theorem
If two lines are perpendicular, then they form congruent adjacent angles