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Basic Geometry Terms
An angle that measures less than 90 degrees.
A triangle with all angles measuring less than 90 degrees.
A figure formed by two rays sharing a common endpoint called the vertex.
Two angles whose measures add to 90 degrees.
Figures with the same size and shape.
The relationship between two or more objects that are matched.
A triangle with three congruent sides.
A triangle with at least two congruent sides.
A straight path that extends without end in opposite directions.
One half of a figure is a mirror image of the other half.
line of symmetry
The imaginary line drawn down the center of a figure with line symmetry.
An angle whose measure is greater than 90 degrees.
A triangle containing one obtuse angle.
Lines in a plane that never intersect.
A quadrilateral with two pairs of parallel sides.
Lines that intersect to form right angles.
A flat surface that extends forever.
An exact location in space.
A closed figure formed by three or more line segments that intersect only at their endpoints.
A part of a line that starts at one endpoint and extends forever in one direction.
A parallelogram with four right angles.
A transformation of a figure that flips the figure across a line.
A polygon with congruent sides and angles.
A regular polygon is repeated to fill a plane.
A parallelogram with all sides congruent.
An angle that measures 90 degrees.
A triangle containing a right angle.
A transformation in which a figure is turned around a point.
A figure can be rotated less than 360 degrees around a central point and coincide with the original figure.
A triangle with no congruent sides.
A part of a line between two endpoints.
A rectangle with four congruent sides.
Two angles whose measures have a sum of 180 degrees.
A repeating pattern of plane figures that completely cover a plane with no gaps or overlaps.
A change in the size or position of a figure.
A movement of a figure along a straight line.
A line that intersects two or more lines.
A quadrilateral with exactly one pair of parallel sides.
Triangle Sum Theorem
The theorem that states that the measures of the angles in a trianlge add up to 180 degrees.
A pair of opposite congruent angles formed by intersecting lines.
Angles formed by a transversal cutting through 2 or more lines that are in the same relative position.
A four sided figure
A five sided figure
A six sided figure
A seven sided figure
An eight sided figure