Definitions
"A line is a breadthless length."
What is Defn. 2?
This Common Notion states: "things which are equal to the same thing are equal to one another."
What is C.N. 1?
An angle that is greater than a right angle.
What is an obtuse angle?
Postulate 2.
What is "Given a finite straight line, we can extend that line as far as needed in a straight line"?
The extremities of a line.
What are points?
The kind of things contained by a boundary or boundaries.
What is a figure?
Common Notion 5.
What is "The whole is greater than the part"?
What is a straight line?
This Postulates states that we can draw circles.
What is Post. 3?
That which has length and breadth only.
What is a surface?
The kind of surface that is flat, with no bumps or bends.
What is a plane surface?
This Common Notion states: "if equals be subtracted from equals, the remainders are equal".
What is C.N. 3?
What we call two lines, one standing on the other, that make adjacent angles equal.
What are perpendicular lines?
Postulate 4.
What is "All right angles are equal"?
The three kinds of rectilinear figures.
What are Trilateral, Quadrilateral, and Multilateral Figures?
The name for an angle made with straight lines.
What is a Rectilinear Angle?
Common Notion 2.
What is "if equals be added to equals, the wholes are equal"?
The definition that states "A circle is a plane figure contained by one line such that all the straight lines falling upon it from one point among those lying within the figure are equal to one another."
What is Defn. 15?
This Postulate states: if a straight line crosses two others so that the inside angles, made on one side, together are less than two right angles, then the two lines will intersect on that side when drawn indefinitely.
What is Post. 5 or "Parallel Postulate"?
These lines are straight, in the same plane, and do not meet one another when extended indefinitely in both directions.
What are parallel lines?
These three kinds of triangles are classified by their sides, not by their angles.
What are Equilateral, Isosceles, and Scalene Triangles?
Common Notion 4.
What is "Things which coincide with one another are equal to one another"?
These are the five kinds of quadrilaterals.
What is a Square, Rectangle, Rhombus, Rhomboid, and Trapezia?
This is the meaning of the word "Postulate."
What is "to assume something as true without proof"?
This definition states "When a straight line set up on a straight line makes adjacent angles equal to one another, each of the angles is called right..."
What is Defn. 10?