Math terms 1

point

circular dot

line

infinite amount of points connected denoted by arrowheads

plane

a sheet of paper made up of points extending in all directions

postulates

basic laws geometry

theorems

rules based on postulates

postulate 2

every line has to contain at least 2 points

postulate 2.2

2 points can only be connected by 1 line

postulate 2.3

if 2 points are in a plane then the line is also in the plane

2.4

3 non-colinear points are contained in one plane only, every plane contains at least 3 non-colinear points

postulate 2.5

in space there exists a least four points not all coplaner

postulate 2.6 (ruler postulate)

how to calculate distance

congruent

the same length

ray

one side is an endpoint while the other is infinite

angle

two line segments/rays meeting at a vertex

acute angle

between 0-90

right angle

exactly 90

obtuse angle

90-180

straight angle

exactly 180

reflex angle

between 180-360

complementary

2 or more angles that equal 90

supplementary

2 or more angles that equal 180

adjacent

2 angles that share a side between the two sides

triangle

polygon formed by three non-colinear points

equilateral

all three sides are congruent

isosceles

at least two sides are congruent

scalene

no sides are congruent

acute triangle

all 3 angles are <90

right triangle

1 angle = 90

hypotenuse

longest side in right angle

obtuse triangle

1 angle is >90

equalangular

all angles = 60

circle

simple and closed

infinity sign

closed not simple

line

simple not closed

trapezoid

four sides with at least on pair of parallel lines

parallelogram

four sided where both sides are parallel and equal length

quadrilateral

four sided shape

rectangle

four sided with all angle measuring 90 all sides are parallel

square

four equal parallel sides at 90 degrees each

kite

four sided with two pairs of adjacent sides that are equal in length

rhombus

four sided shape where all sides are equal

reflection symmetry

matching halves could evenly fold

rotation symmetry

after a turn of <360 the shape matches