Chapter 11 Geometry Vocabulary

point

point

exact location (GPS)

line

atleast two points, and continues forever in both directions

line segment

part of a line you can measure

ray

you know where it starts and it continues in one direction

angle

when two rays share a common end point (vertex)

vertex

end point

sides

consists of line segments

degree

a unit of measure for angles

right

exactly 90 degrees

acute

less than 90, but greater than 0

obtuse

bigger than 90, but less than 180

straight

measures 180

plane

flat surface that extends forever in all directions (floor, wall)

parallel lines and perpendicular lines

continues forever in both directions, lie in same plane, same distance apart, never intercept, and same slope

skew lines

don’t lie in the same plane, and don’t intercept

complementary lines

2 angles = 90 (c, 90) (c before s, and 90 before 180)

supplementary lines

2 angles = a straight line (180) (s after c, 180 after 90)

acute triangles

all angles are less than 90

right triangles

one angle is 90 (makes a square at the corner)

obtuse triangles

one angle greater than 90

equilateral triangles

all sides are the same length (60 each) (60 x 3 = 180) (3 sides = triangle)

isosceles triangles

two sides that are exactly the same length + angles have same measurements

scalene triangles

every side has a different measure, usually one line is obtuse

Congruent Statement

Ex: ABC = XYZ

Corresponding Parts

a = x | b = y | c = z | ab = xy | bc = yz | ac = xz

transversal

crosses at least two parallel lines and forms special angles

alternate interior angles

inside parallel lines

alternate exterior angles

angles that are outside of parallel lines, and alternate on transversal

corresponding angles

angles that lie on same location, but on different lines

similar triangles

the measures of corresponding angles are equal, and the measures of corresponding sides are proportional

congruent

quadrilateral

4-sided figure (360 total degrees)

parallelogram

two pairs of parallel sides, opposite sides are equal, have to have 360

rectangle

two pairs of parallel sides, all angles are 90 degrees (a square can be a rectangle, but a rectangle cannot be a square)

square

two pairs of parallel sides, all sides are congruent, all sides are 90 degrees (a square can be a rectangle, but a rectangle cannot be a square)

rhombus

all sides have same measure, two pairs of parallel sides (equal)

pentagon

five-sided figure (total degree = 540)

he__x__agon

si__x__-sided figure (total degree = 720)

heptagon

seven-sided figure (total degree = 900)

octagon

eight-sided figure (total degree = 1080)

__non__agon

__nin__e-sided figure (total degree = 1260)

__deca__gon

ten-sided figure (decade) (total degree = 1440)

dodecagon

twelve-sided figure (total degree = 1800)

trapezoid

one pair of parallel sides

total degree formula

(n - 2)180 (n = amount of triangles formed)

regular polygon formula

find total degree, then divide by the sides | Ex: 900 / 7 = 128.7 for every angle

adjacent angles

angles in a transvertical that are across from each other