36 terms

point

an exact location in space

line

an endless collection of points along a straight path

line segment

part of a line that has two end points

ray

part of a line that has one endpoint and extends endlessly in the other direction

plane

an endless flat surface that is named by any three parts not in the same line

intersecting lines

lines that have exactly one point in common; lines that touch

parallel lines

lines in the same plane that never intersect; lines that never touch

perpendicular lines

two lines that intersect at right angles

acute angle

an angle that measure less than 90 degrees

right angle

an angle that measures 90 degrees

obtuse angle

an angle with a measure greater than 90 degrees but less than 180 degrees

straight angle

an angle that measures 180 degrees

polygon

a closed plane figure with 3 or more sides

quadrilateral

a 4 sided polygon

pentagon

a 5 sided polygon

hexagon

a 6 sided polygon

heptagon

a 7 sided polygon

octagon

a 8 sided polygon

nonagon

a 9 sided polygon

decagon

a 10 sided polygon

acute triangle

a triangle with 3 acute angles

obtuse triangle

a triangle with one obtuse angle

equilateral triangle

a triangle with all sides equal

isosceles triangle

a triangle with two congruent sides

scalene triangle

a triangle that has no congruent sides

parallelogram

a quadrilateral with 2 sets of parallel sides

rhombus

a parallelogram with 4 equal sides

square

a parallelogram with 4 right angles and 4 equal sides

rectangle

a parallelogram with 4 right angles

trapezoid

a quadrilateral with only 1 set of parallel sides

vertex

where edges meet

edge

where faces meet on a space figure

face

a flat surface on a space figure

right triangle

a triangle with one right angle

congruent

same shape same size

similar

same shape different size