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Geometry

Geometry vocabulary terms for MSM 1 and MSM 2.
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Plane
A flat surface that extends indefinately in all directions.
Point
A dot that represents a location on a plane.
Line
A collection of points that extend indefinately in both directions.
Line Segment
Part of a line consisting of two endpoints and all the points between them.
Ray
Part of a line that has one endpoint and extends indefinately in one direction.
Polygon
A closed figure whose sides are straight line segments.
Triangle
A polygon with 3 sides.
Quadrilateral
A polygon with 4 sides.
Pentagon
A polygon with 5 sides.
Hexagon
A polygon with 6 sides.
Heptagon
A polygon with 7 sides.
Octagon
A polygon with 8 sides.
Nonagon
A polygon with 9 sides.
Decagon
A polygon with 10 sides.
Parallelogram
A quadrilateral with opposite sides parallel.
Rectangle
A parallelogram with 4 right angles.
Square
A rectangle with 4 sides of equal length.
Rhombus
A parallelogram with 4 sides of equal length.
Trapezoid
A quadrilateral with exactly one pair of parallel sides.
Types of Quadrilaterals
Parallelograms, rectangle, rhombus, trapezoid, square
Similar Figures
Figures that have the same shape but not necessarily the same size.
Corresponding Sides
A pair of sides from similar figures that are in the same position.
Corresponding Angles
A pair of angles from similar figures that are in the same position.
Congruent
To have the same measure.
Perpendicular Lines
Two lines that intersect at a right angle
Pi
The number that is the ratio of circumference of a circle to its diameter. 3.14159
Circle
The set of all points in a plane that are the same distance from a given point called the center
Radius
A line segment that has the center as one endpoint and a point on the circle as the other endpoint.
Diameter
The distance across a circle through the center.
Circumference
The distance around a circle.
Right Triangle
A triangle that has one right angle.
Hypotenuse
The side of a right triangle that is opposite the right angle. The longest side of a right triangle.
Legs
The sides of a right triangle that form the right angle.
Pythagorean Theorm
a2 + b2 = c2
Volume
The measure of the amount of space that an object occupies or how much it will hold. It is measured in cubic units.
Surface Area
The sum of the area of all the faces of a solid figure. SA is measured in square units.
Face
The flat surface of a solid figure.
Polyhedra
A solid that is bounded by polygons.
Square Pyramid
A figure whose base is a square and whose other faces are triangles that share a common vertex.
Rectangular Prism
A prism whose base is a rectangle.
Cone
A solid that has a circular base, a vertex, and a lateral surface area.
Cylinder
A solid figure with congruent circular bases that lie in parallel planes.
Ordered Pair
(x, y) Where x and y are values representing a point on a coordinate plane.
Rotation
A transformation that turns a figure a given angle and direction around a point.
Reflection
A transformation that flips a figure about a line into its mirror image on the opposite side of the line.
Translation
A transformation that slides each point of a figure the same distance in a given direction.
Dialation
Enlarging or reducing a figure proportionally.
Scale Factor
The common ratio of one polygon to a similar polygon.