Geometry Basic Vocabulary

perpendicular lines

• lines that form a perfect right angle (90 degrees) when they intersect (cross)

• lines that run parallel to each other without ever meeting

• lines that intersect at any angle other than 90 degrees

• lines that are completely vertical or horizontal

rhombus

• a quadrilateral with 4 congruent (equal sides)

• a polygon with 5 sides

• a quadrilateral with opposite sides equal

• a shape with all angles equal

• circle

• triangle

• rectangle

• square

What is a quadrilateral?

• A polygon with four sides, four angles, and four vertices.

• A shape with three sides and three angles.

• A figure with five sides and five angles.

• A closed figure with six sides and six angles.

trapezoid

• a quadrilateral with exactly one pair of parallel lines

• a polygon with four equal sides

• a triangle with one right angle

• a shape with no parallel sides

acute angle

• An angle that is LESS than a right angle (90 degrees)

• An angle that is exactly 90 degrees

• An angle that is greater than 90 degrees but less than 180 degrees

• An angle that is greater than 180 degrees

parallel lines

• lines that are the same distance apart and never cross

• lines that intersect at a right angle

• lines that meet at a single point

• lines that are curved and do not follow a straight path

equilateral triangle

• a triangle with all three sides congruent

• a triangle with two sides of equal length

• a triangle with one right angle

• a triangle with all sides of different lengths

vertex

• the point where two sides of a polygon meet

• a line segment connecting two vertices

• the area enclosed by a polygon

• the angle formed by two intersecting lines

kite

• a quadrilateral with two distinct pairs of adjacent sides that are equal

• a polygon with all sides equal

• a quadrilateral with opposite sides equal

• a triangle with two equal sides