Geometry Flashcards
A line
<——->
A half line
o———>
Line segment
A o———o B
Acute angle
Less than 90 degrees
Obtuse angle
greater than 90 degrees
Reflex angle
Betweeen 180 - 360 degrees
Right angle
90 degrees
Straight angle
180 degrees
Full angle
360 degrees
vertically opposite angles
X shape
Alternate angles
Z shape
Corresponding angles
F shape
Interior angles
C shape
/c \ / \ /A B\D D =
Exterior angle
Properties of Parrallelogram
Opp sides are equal + parrallel
Opp angles are equal
Diagonals bisect each other
Congruent triangles
SSS (Side, Side, Side)
SAS (Side, Angle, Side)
ASA (Angle, Side, Angle)
RHS (Right angle, Hypotenuse, Other side)
Theorems: Vertically opposite angles are…
Equal in measure
Theorems: In an isosceles triangle, thw angles opposite the equal sides are…
Equal
Theorems: If a transversal makes equal alternative angles on 2 lines, the lines are…
Parallel
Theorems: 2 lines are parallel if the corresponding angles in the transversal are…
Equal
Theorems: Each exterior angle is equal to
The sum of the opposite interior angles
Theorems: In a parallelogram, opposite sides/angles are
Equal
Theorems: The diagonals of a parallelogram…
Bisect each other
Theorems: If 2 triangles are similar, their sides are…
Proportional
Theorems: Pythagoras’ theorum
Hypotenuse squared = other 2 sides squared
Axiom
A statement that we accept without any proof: e.g. There is exactly one line through any two given points
theorem
A rule that you can prove by following a certain number of logical steps or using a previous theorem or axiom.
E.g. Pythagoras’ Theorem
Proof
a series of logical steps that we use to show a theorem is true
Corollary
a statement that follows readily from a
previous theorem
Converse
reversing the order of a statement
