Satisfy yourself that the first 3 statements in Equivalent Forms of Euclid's Fifth Postulate are consequences of Axiom P-1: These statements are: 1. The area of a right triangle can be made arbitrarily large 2. The angle sum of all triangles is constant 3. The angle sum of a simple triangle=180 Axiom P-1 states: If l is any line and P does not belong to l, there exists a unique line passing through P parallel to l (in the plane of P,l)

Satisfy yourself that the first 3 statements in Equivalent Forms of Euclid's Fifth Postulate are consequences...
2) (i) State the converse of the Alternate Interior Angle Theorem in Neutral Geometry. (ii) Prove that if the converse of the Alternate Interior Angle Theorem is true, then all triangles have zero defect. [Hint: For an arbitrary triangle, ABC, draw a line through C parallel to side AB. Justify why you can do this.] 5) Consider the following statements: I: If two triangles are congruent, then they have equal defect. II: If two triangles are similar, then they have...
7. (10) Find the flaw in the following attempted proof of the parallel postulate by Wolfgang Bolyai (Hungarian, 1775 - 1856) (see Fig. 3). Given any point P not on a line l, construct a line 1' parallel to through P in the usual way: drop a perpendicular PQ to / and construct /" perpendicular to PQ. Let I" be any line through P distinct from l'. To see that /" intersects I, pick a point A on PQ between...