# Geometric Terms

shape term definition Perpendicular Line Segments two line segments which cross to form 90 degree angles Right Angle a 90 degree angle Equilateral Triangle a triangle with all sides equal and all angles equal Scalene Triangle a triangle having three unequal sides and angles Vertex the intersection point of two sides of a plane figure Right Triangle a triangle with one internal angle equal to 90 degrees Pentagon a polygon with 5 sides and 5 angles Square a rectangle having all four sides of equal length Intersecting Line Segments line segments that cross each other Acute Angle an angle less than 90 degrees but greater than 0 degrees Chord the line segment between two points on a given curve Radius a straight line extending from the center of a circle or sphere to the circumference or surface Line Segment one part of a line Line a continuous extent of length Point a position in space Parallelogram a quadrilateral having both pairs of opposite sides parallel to each other
Note: squares and rectangles are also quadrilaterals Rectangle a parallelogram having four right angles
Note: a square is also a rectangle Rhombus an equilateral parallelogram having oblique angles Parallel Line Segments line segments that do not intersect Quadrilateral a polygon with four sides
Note: squares, rectangles and trapezoids are also quadrilaterals Octagon a polygon having eight angles and eight sides Circle a closed plane curve consisting of all points at a given distance from a point within it called the center Trapezoid a quadrilateral plane figure having two parallel and two nonparallel sides Ray the part of a straight line considered as originating at a point on the line and as extending in one direction from that point Closed Curve a curve that is continuous and has endpoints that meet at the same point Isosceles Triangle a triangle which has two sides equal Hexagon a polygon having six sides and six angles Diameter a straight line passing through the center of a circle or sphere and meeting the circumference or surface at each end Obtuse Angle an angle greater than 90 degrees but less than 180 degrees