34 terms

# Geometry Vocabulary

#### Terms in this set (...)

acute angle
An angle that measures less than 90 degrees.
acute triangle
A triangle in which all three angle are less than 90 degrees.
angle
Two rays that share a common endpoint.
supplementary angles
adjacent angles that equal 180 degrees
complimentary angles
Adjacent angles that equal 90 degrees.
area
The number of square units inside a closed figure.
circle
A closed round shape with a measure of 360 degrees.
intersecting lines
Lines that cross each other at a point.
line
A straight path that goes on forever in both directions.
obtuse angle
An angle that is bigger than a right angle.
obtuse triangle
A triangle with one obtuse angle.
parallel lines
Lines that will never cross, even if they are extended forever.
perimeter
The distance around the outside edge of a closed figure.
perpendicular lines
Lines that form right angles where they cross.
polygon
A closed figure made up of line segments.
A polygon with 4 sides and 4 angles.
pentagon
A polygon with 5 sides and 5 angles.
hexagon
A polygon with 6 sides and 6 angles.
octagon
A polygon with 8 sides and 8 angles.
rectangle
A quadrilateral with 4 right angles.
square
A quadrilateral with 4 right angles and 4 equal sides.
trapezoid
A quadrilateral with one pair of parallel sides.
parallelogram
A quadrilateral with two pairs of opposite parallel sides.
rhombus
A quadrilateral with two pairs of parallel sides, and all 4 sides of equal length.
ray
A straight path with one endpoint, that goes on forever in the other direction.
right angle
An angle with a measurement of exactly 90 degrees.
line segment
A straight path between two endpoints.
line of symmetry
A line that cuts a figure into two parts that are the mirror image of each other.
straight angle
An angle that measures exactly 180 degrees.
equilateral triangle
A triangle with 3 equal sides and 3 acute angles that are also equal.
isosceles triangle
A triangle with 2 equal sides.
scalene triangle
A triangle with no equal sides.
right triangle
A triangle with one right angle.
triangle
A polygon with 3 sides and 3 angles