Congruent
Two shapes with the same shape and size.
Parallel
Lines that are the same distance apart and will never intersect.
Perpendicular
Two lines that intersect and create a right angle.
Quadrilateral
A flat shape with four straight sides.
Angle
The space between two intersecting lines usually measured in degrees.
Vertex
A point where two or more straight lines meet.
Ray
A line with a start point but no end point (it goes on to infinity).
Acute Angle
An angle less than 90°.
Obtuse Angle
An angle more than 90° but less than 180°.
Right Angle
An angle exactly 90°.
Parallelogram
A quadrilateral in which the opposite sides are parallel, the opposite sides have the same length, and the opposite angles have the same measure.
Rhombus
A type of parallelogram where all sides have an equal length.
Triangle
A three-sided polygon.
Scalene Triangle
A triangle with all sides of different lengths.
Isosceles Triangle
A triangle with only two sides with same lengths.
Equilateral Triangle
A triangle with all sides the same length.
Circle
A shape made by drawing a curve that is always the same distance from the center.
Pi
An irrational number used to calculate circumference and area.
Circumference
The distance around the edge of a circle.
Diameter
A straight line going through the center of a circle connecting two points on the circumference.
Radius
The distance from the center to the edge of a circle.
Square
A quadrilateral where all sides have equal length, and every angle is a right angle.
Rectangle
A quadrilateral where every angle is a right angle, the opposite sides are parallel, and the opposite sides have an equal length.
Area
The amount of square units covered by a figure.
