Ch. 7 - Geometry Flashcards
Geometry
The study of points, lines, angles, surfaces and solids
Line Segment
Part of a line
Ray
A line that has a beginning point but no end
Angle
Two rays with the same endpoint
Vertex
The point where two rays meet
Plane
A flat surface that extends forever in all directions
Parallel Lines
Lines that are always the same distance apart
Intersecting Lines
Lines that cross in the same plane
Perpendicular Lines
Intersecting lines that cross and form four right (90*) angles
Circle
A plane figure whose points are equally distant from the center
Degree
A measure of angles
Acute Angle
Less than a right angle (between 0* and 90*)
Right Angle
Formed by two perpendicular rays (90*)
Obtuse Angle
Larger than a right angle but smaller than a straight angle (between 90* and 180*)
Straight Angle
Two rays form a straight line (180*)
Reflex Angle
Larger than a straight angle (between 180* and 360*)
Protractor
A tool used to draw or measure angles
Polygon
A closed plane figure with three or more sides
Polygon Names
3 sides - Triangle
4 sides - Quadrilateral
5 sides - Pentagon
6 sides - Hexagon
7 sides - Heptagon
8 sides - Octagon
9 sides - Nonagon
10 sides - Decagon
12 sides - Dodecagon
Triangle
A polygon with three sides
Right Triangle
One angle is 90*
Obtuse Triangle
One angle is more than 90*
Acute Triangle
All angles are less than 90*
Scalene Triangle
No sides are equal
Isosceles Triangle
Two sides are equal
Equilateral Triangle
All three sides are equal
Quadrilateral
A polygon with four sides
Square
A polygon with four equal sides and four right angles
Rectangle
A four-sided polygon with four right angles and the opposite sides are equal
Rhombus
A polygon with four equal sides and the opposite angles are equal
Parallelogram
A four-sided polygon with two pairs of equal and parallel sides
Trapezoid
A four-sided polygon with one pair of parallel sides and one pair of sides that are not parallel
Prism
A solid figure with two parallel faces that are polygons of the same shape
Cube
A prism with square sides and faces
Pyramid
A solid figure with a base that is a polygon and triangular sides
Triangular Prism
A prism with triangular faces
Hexagonal Prism
A prism with hexagonal faces
Rectangular Prism
A prism with rectangular faces
Cylinder
A solid figure with two equal circular bases that are parallel
Cone
A solid figure with a circular base connected to a vertex
Sphere
A solid figure with a curved surface in which all points on the surface are equal distance from the center
