plane

a flat surface that goes on and on in each direction

point

a particular place on a plane - named with a letter

end point

a point at the start of a ray or at either end of a line segment

line

a straight path that goes on without end in opposite directions. name a line segment by naming only 2 points on that line

line segment

a place on a straight line- name a line segment by naming the 2 endpoints

ray

has an endpoint and goes on forever in one direction. Must name the endpoint first and then name any other point on the ray

intersecting lines

lines that cross, where they cross is called the point of intersecting

parallel lines

lines that are always the same distance apart. They will never intersect.

perpendicular lines

lines that intersect to form right angles

angle

two rays that share a common endpoint

vertex

the endpoint that 2 rays have in common.

The vertex is always named in the middle of an angle

The vertex is always named in the middle of an angle

right angle

measures 90 degrees - a corner

acute angle

measures less than 90 degrees, less than a right angle

obtuse angle

measures greater than 90 degrees, more than a right angle

polygon

a closed figure (plane) made up of line segments

non polygon

a closed figure made up of any shape with curves

triangle

a plane with three sides

acute triangle

3 acute angles - all angles are less than 90 degrees

obtuse triangle

1 obtuse angle - more than 90 degrees

right triangle

1 right angle - a 90 degree angle

equilateral triangle

all 3 sides are equal in length

isosceles triangle

2 sides are equal in length and 2 angles are equal

scalene triangle

all 3 sides are different in length all angles are different measurements

quadrilateral

a plane figure with 4 sides

parallelogram

a quadrilateral with 2 pairs of parallel sides

square

all sides are the same length and has 4 right angles

rectangle

opposite sides are parallel, equal in length and has 4 right angles

trapezoid

quadrilateral with only 1 pair of parallel lines

rhombus

quadrilateral with 2 pairs of parallel sides, all sides are the same length

similar

2 figures that are the same shape but not the same size

congruent

2 figures that are the same shape and the same size

reflection

flip- over a line

translation

slide- a figure across a line

rotation

turn - a figure around a point

symmetry

a figure that can be folded on a line to form 2 congruent halves

chord

a line that connects 2 points on a circle

diameter

distance from one end of a circle to the other

radius

line segment from the center of the circle to every point on a circle

circumferences

the distance around the outside of a circle

perimeter

the distance around a closed figure (units)

area

the number of square units needed to cover a figure ( square units)

volume

the number of cubic units to cover a figure ( cubic units)

face

a flat surface of a solid

edges

a line segment where 2 faces of a solid figure meet