Vocabulary Geometry
point
an exact location in space
acute angle
an angle that is less than 90 degrees and smaller than a right angle
Hexagon
a polygon with 6 sides and 6 vertices
intersecting lines
the 2 line segments cross each other at a point
parallel lines
lines that are equal distance apart at every point and they never intersect
The strips on the monarch caterpillar are parallel.
symmetric
symmetrical
lines of symmetry
a figure is symmetric if it can be folded into 2 congruent halves that fit on top of each other. The line of symmetry divides the valentine heart into 2 congruent shapes.
line
a straight path of points that goes on forever in both directions
plane
an endless flat surface
perpendicular lines
2 lines that intersect at a right angle
line segment
part of a line that has 2 end points
ray
part of a line that has 1 end point and extends forever in one direction
angle
a figure formed by 2 rays that have the same endpoint
right angle
an angle that measures exactly 90º
obtuse angle
and angle that measures more than 90º
straight angle
an angle that measures exactly 180º
polygon
a closed shape made up of line segments
side
each of the line segments of a polygon
vertex, vertices
the point where 2 rays meet to form an angle. the points where the sides of a polygon meet.
triangle
a polygon with 3 sides and 3 angles
quadrilateral
a polygon with 4 sides and 4 angles
pentagon
a polygon with 5 sides and 5 angles
octagon
a polygon with 8 sides and 8 angles
parallelogram
a quadrilateral in which the opposite sides are parallel
rectangle
a parallelogram with 4 right angles
square
a parallelogram with 4 right angles and all sides the same length
rhombus
a parallelogram with all sides the same length
trapezoid
a quadrilateral with only 1 pair of opposite sides that are parallel
equilateral triangle
a triangle with 3 equal sides
isosceles triangle
a triangle that has 2 equal sides
scalene triangle
a triangle that has no sides that as the same length
right triangle
a triangle with 1 right angle
acute triangle
a triangle with 3 acute angles
obtuse triangle
a triangle with one obtuse angle
congruent
2 shapes that are the same shape and the same size
similar
2 shapes that are the same shape but not the same size
classify
To arrange in groups, by some property.
These shapes are classified by the number of sides.
ellipse
a 2 dimensional shape that resembles a flatten circle
An ellipse has only 2 lines of symmetry
equiangular
two dimensional
a shape that has height and width but no depth, Squares, Circles, Triangles, etc are two dimensional objects
congruent polygons
2 polygons that are the same shape and same size