Geometry Flashcards
Angles on opposite sides of an X shape
Vertically opposite
Angles that are equal on Z shape
Alternate angles
Equal angles on F shape
Corresponding angles
Interior angles between two parallel lines add up to
180°
Each exterior angle of a triangle is equal to …
The sum of the interior opposite angles
Triangle inequality theorem:
Two sides of a triangle are together greater than the third
What is a polygon
A closed shape with at least 3 sides
In a parallelogram opposite sides are
Equal and parallel
In a parallelogram opposite angles are
Equal
In a rhombus, diagonals bisect eachither…
At a 90°angle
Chord
Any segment that joins two points on a circle
Arc
Any part of the circumference
Opposite angles in a cyclic quadrilateral add up to
180°
A tangent to a circle is at an X° angle to the radius at the point of contact
90°
Proposition
A mathematical statement or theorem that may be true or false
A proof
A series of logical steps that we use to prove a statement
A theorem
A statement that has been proved using a series of logical steps
Axiom
A statement we accept without any proof
Corollary
A statement that follows readily from a previous theorem
A converse
A theorem formed by swapping the order of the hypothesis and the conclusion
Congruent triangles
Triangles where all corresponding sides and interior angles are equal in measure
4 types of congruent triangles
SSS
SAS
ASA
RHS
Circumcentre is the
Intersection of the perpendicular bisectores
Intercentre is the
Intersection of the angle bisectores
Circumcircle is
Circle on which all vertexes of triangle are on the line of the circle
Incircle
Circle inside the triangle. The centre is equidistant from all sides of the triangle
The centroid is
Where the medians intersect
What is a median of a triangle
Midpoint of line attached to vertex on opposite side
Orthocentre is
Where the altitudes intersect
What are the altitudes
The vertex to the opposite side perpendicularly
What is the centre of gravity also called
Centroid
