# Geometry Vocabulary 2

## Terms

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- Angle
- Corner formed by the intersection of 2 line segments, rays, or lines
- Area
- Space occupied by a 2D figure
- Base
- The # in a expression that has a power or exponent above it; the line or plane upon which a geometric firgure is thought of as resting.
- Circumference
- The distance measured by the line bounding a circle
- Complement
- For any event E, there is a corresponding event consisting of all the outcomes not in E.
- Complementary angles
- 2 angles whose measures total 90 degrees
- Cone
- A 3D figure with a circular base and the top meeting at a vertex; it resembles a funnel.
- Congruent
- 2 measures with the exact same value
- Cross-multiplying
- Multiplying the denominator of one ratio in a proportion by the numerator in the other ration and vice versa.
- Cylinder
- A 3D figure with 2 circular bases; resembles a can
- Deca
- Metric prefix meaning "ten"
- Decagon
- a ten sided polygon
- Deci
- Metric prefix meaning "one-tenth"
- Denominator
- the bottom number in a fraction; it idicates into how many parts the whole is divided.
- Dodecagon
- a 12 sided polygon
- Edge
- a line or line segment at which 2 plane surfaces meet
- Face
- anyone of the surfaces of a geometric figure
- Heptagon
- a 7 sided polygon
- Hexagon
- a 6 sided polygon
- Hyptenuse
- The longest side of a right triangle, located opposite the right angle
- Icosagon
- a 20 sided polygon
- Interest
- Money paid for the use of money expressed as a percentage per unit of time
- Line
- Continuously connected points extending to infinity
- Line segment
- Continously connected points with 2 distinct start and end points
- Liter
- Metric unit of measure for volume or capacity
- Milli
- Metric prefix meaning "one- thousandth"
- Nonagon
- a 9 sided polygon
- Obtuse angle
- An angle whose measure is greater than 90 degrees
- Octagon
- An 8 sided polygon
- Orderd pair
- the x- axis coordinate and the y- axis coordinate (x, y)
- Parallelogram
- a quaderlateral w/ both pairs of opposite sides parallel
- Pentagonal prism
- a prism with 2 pentagonal bases
- Pentagonal pyramid
- a pyramid with a pentagonal base
- Perimeter
- distance around a figure
- Pi
- the ratio of a circumference of a cirlce to its diameter; the aprox. value is 3.14
- Polygon
- a closed plane figure; 2D figure
- Polyhedron
- a solid figure; 3D figure
- Principal
- the amount of debt or investment minus the interest
- Prism
- a 3D object with rectangles for sides or faces
- Probability
- A # from 0 to 1 that states the likelihood an event will occur
- Proportion
- an equation with 2 equal ratios on each side of the equal sign
- Pyramid
- a 3D figure with triangles for sides or faces
- Quadrilateral
- a 4 sided polygon
- Radius
- A straight line extending from the center of the circle or sphere to the periphery
- Ratio
- a comparison of 2 #'s; can be written in the form 1/4 1:4 or 1 to 4
- Ray
- A line extending in one direction from a fixed point
- Reciprocal
- THe inversion of a fraction (the numerator becomes the denominator and the denominator becomes the numerator)
- Rectangle
- a parallelogram with 90 degree angles
- Rectangular Prism
- a prism with 2 rectangular bases
- Rectangular pyramid
- a pyramid with a rectangular base
- Regular
- a 2D figure with all sides the same length and all angles the same measure
- Rhombus
- a parallelogram with sides of equal length
- Right angle
- an angle whose measure is exactly 90 degrees
- Right triangle
- a triangle with one right angle
- Rise
- how many units up or down a line travels on a graph b/w 2 points
- Run
- how many units left or right a line travels on a graph b/w 2 points
- Scale
- A form of ratio often used in maps or models where the first number is the dimension of the map or model and the 2nd # is the dimension of the actual object; written in the form 1:4
- Simple interest
- found by multiplying the principal by the annual interest rate and then multiplying the result by the # of years or time; i= p*r*t
- Similar triangles
- if each side of 1 triangle can be multiplied by the same # and the result is the length of each side of a second triangle
- Slant height
- The height of a lateral side in a 3D figure
- Slope
- Ratio of the rise to the run
- Sphere
- a 3D figure that is completely circular in width and height; looks like a hollow ball
- Square
- a parallelogram with 90 degrees and sides of equal length
- Trapezoid
- a quadrilateral with only 1 pair of opposite sides parallel
- Triangle
- a 3 sided figure
- Triangular prism
- a prism with 2 triangular bases
- Triangular pyramid
- a pyramid with a triangular base
- Vertex
- the point where an angle is formed; the corner point of a geometric figure
- Vertical angles
- opposite angles formed when 2 lines or line segments intersect; the angle measures are congruent
- Volume
- space occupied by a 3D figure
- Supplementary angles
- 2 angles whose measures total 180 degrees
- Surface Area
- Sum of the area of each base and face of a 3D figure