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 BOOK I 5 DEFINITIONS POSTULATES AXIOMS 11 SECTION II 56 SECTION III 72 Theorems and Examples on Book I 95 ON INEQUALITIES 101 VI 110 ON AREAS 117
 Theorems and Examples on Book IV 297 PROPOSITIONS 116 309 Elementary Principles of Proportion 317 DEFINITIONS 325 Theorems and Examples on Book VI 384 ON POLE AND POLAR 390 ON THE RADICAL AXIS OF TWO OR MORE CIRCLES 396 BOOK XI 409

 BOOK III 163 Theorems and Examples on Book III 233 BOOK IV 268
 PROPOSITIONS 121 419 EXERCISES ON BOOK XI 444

### ƒзмпцйлё брпур№умбфб

”елядб 353 - Pythagoras' theorem states that the square of the length of the hypotenuse of a right-angled triangle is equal to the sum of the squares of the lengths of the other two sides.
”елядб 340 - If two triangles have one angle of the one equal to one angle of the other and the sides about these equal angles proportional, the triangles are similar.
”елядб 65 - If two triangles have two angles of the one equal to two angles of the other, each to each, and also one side of the one equal to the corresponding side of the other, the triangles are congruent.
”елядб 162 - AB into two parts, so that the rectangle contained by the whole line and one of the parts, shall be equal to the square on the other part.
”елядб 326 - From this it is manifest that prisms upon triangular bases, of the same altitude, are to one another as their bases. Let the...
”елядб 162 - If a straight line be bisected and produced to any point, the rectangle contained by the whole line thus produced and the part of it produced, together •with the square...
”елядб 291 - The side of a regular hexagon inscribed in a circle is equal to the radius of the circle.
”елядб 79 - The straight line joining the middle points of two sides of a triangle is parallel to the third side and equal to half of it 46 INTERCEPTS BY PARALLEL LINES.
”елядб 18 - THE angles at the base of an isosceles triangle are equal to one another : and, if the equal sides be produced, the angles upon the other side of the base shall be equal.
”елядб 242 - We may here notice that the perpendiculars from the vertices of a triangle to the opposite sides are concurrent ; their meet is called the orthocentre, and the triangle obtained by joining the feet of the perpendiculars is called the pedal triangle.