postulates and theroms and stuff Flashcards
(43 cards)
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
converse of the perpendicular theorem
If two lines form congruent adjacent angles, then the lines are perpendicular
If the exterior sides of two adjacent acute angles are perpendicular, then what theorem
If the exterior sides of two adjacent acute angles are perpendicular, then the angles are complementary
if two angles are supp of congruent angles, then
If two angles are supplements of congruent/ same angles, then the two angles are congruent
if two angles are comp of congruent angles, then
if two angles are complements of congruent/ same angles, then the two angles are congruent
Scalene
no sides are congruent
Isosceles
at least 2 sides are congruent
Equilateral
all sides are congruent