Geometry
mathematics dealing with lines, angles, surfaces, and solids
point
A location in space.
line
collection of points that extend forever in the same direction.
line segment
part of a line
ray
collection of points that begin at one point and extend forever in one direction.
plane
Flat surface that extends forever in all directions.
parallel lines
Two lines that are always the same distance apart and are going in the same direction.
intersecting lines
Lines that meet or cross at a common point.
perpendicular lines
Lines that meet in such a way that the four angles formed are all the same size.
acute angle
an angle that measures less than 90 degrees
right angle
equal to 90 degrees
obtuse
angle larger than 90 degrees but smaller than 180
straight
Two rays that form a straight line. Exactly 180 degrees
vertex
The common endpoint of an angle.
angle
formed by two rays with the same endpoint
right triangle
a triangle with one right angle
obtuse triangle
A triangle with one angle that is greater than 90 degrees.
Acute triangle
A triangle with 3 acute angles
Scalene Triangle
a triangle with no congruent sides
Isosceles triangle
triangle that has two sides of equal length.
equilateral triangle
A triangle with three congruent sides
square
A quadrilateral with 4 sides that are equal and has all 90 degree angles
rectangle
a quadrilateral with four right angles
parallelogram
two pairs of equal and parallel sides
Trapezoid
a quadrilateral with one pair of parallel sides