## Euclid's Elements of Geometry: Chiefly from the Text of Dr. Simson, with Explanatory Notes; a Series of Questions on Each Book; and a Selection of Geometrical Exercises from the Senate-house and College Examination Papers, with Hints, &c. Designed for the Use of the Junior Classes in Public and Private Schools. the first six books, and the portions of the eleventh and twelfth books read at CambridgeLongman, Green, Longman, Roberts, and Green, 1868 - 410 pages |

### From inside the book

Results 1-5 of 49

Page 4

...

...

**equilateral triangle**is that which has three equal sides . XXV . An**isosceles triangle**is that which has two sides equal . XXVI . A scalene triangle is that which has three unequal sides . XXVII . A right - angled triangle is that ... Page 10

... triangle ABC ; and it has also been proved , that the angle FBC is equal to the angle GCB , which are the angles upon the other side of the base . Therefore the angles at the base , & c . Q.E.D. COR . Hence an

... triangle ABC ; and it has also been proved , that the angle FBC is equal to the angle GCB , which are the angles upon the other side of the base . Therefore the angles at the base , & c . Q.E.D. COR . Hence an

**equilateral triangle**is ... Page 11

...

...

**triangle**is also**equilateral**. PROPOSITION VII . THEOREM . Upon the same base , and on the same side of it , there cannot be two**triangles**that have their sides which are terminated in one extremity of the base , equal to one another ... Page 13

...

...

**equilateral triangle**DEF ( 1. 1. ) , and join AF . Then the straight line AF shall bisect the angle BAC . Because AD is equal to AE , ( constr . ) and AF is common to the two triangles DAF , EAF ; the two sides DA , AF , are equal to ... Page 14

...

...

**equilateral triangle**DEF ( 1. 1 , ) and join CF. Then CF drawn from the point C , shall be at right angles to AB . Because DC is equal to EC , and FC is common to the two triangles DCF , ECF ; the two sides DC , CF are equal to the ...### Common terms and phrases

A₁ ABCD AC is equal Algebraically angle ABC angle ACB angle BAC Apply Euc base BC chord circle ABC constr demonstrated describe a circle diagonals diameter divided double draw equal angles equiangular equilateral triangle equimultiples Euclid exterior angle Geometrical given circle given line given point given straight line gnomon greater hypotenuse inscribed intersection isosceles triangle less Let ABC line BC lines be drawn multiple opposite angles parallelogram parallelopiped pentagon perpendicular plane polygon problem produced Prop proportionals proved Q.E.D. PROPOSITION quadrilateral figure radius ratio rectangle contained rectilineal figure remaining angle right angles right-angled triangle segment semicircle shew shewn similar similar triangles solid angle square on AC tangent THEOREM touch the circle trapezium triangle ABC twice the rectangle vertex vertical angle wherefore

### Popular passages

Page 6 - If a straight line meets two straight lines, so as to make the two interior angles on the same side of it taken together less than two right angles...

Page 118 - Guido, with a burnt stick in his hand, demonstrating on the smooth paving-stones of the path, that the square on the hypotenuse of a right-angled triangle is equal to the sum of the squares on the other two sides.

Page 2 - When a straight line standing on another straight line makes the adjacent angles equal to one another, each of the angles is called a right angle ; and the straight line which stands on the other is called a perpendicular to it.

Page 317 - If two triangles have two angles of the one equal to two angles of the other, each to each, and one side equal to one side, viz.

Page 90 - If a straight line be divided into any two parts, the squares of the whole line, and of one of the parts, are equal to twice the rectangle contained by the whole and that part, together with the square of the other part. Let the straight line AB be divided into any two parts in the point C; the squares of AB, BC are equal to twice the rectangle AB, BC, together with the square of AC.

Page 88 - If a straight line be divided into two equal parts, and also into two unequal parts; the rectangle contained by the unequal parts, together with the square of the line between the points of section, is equal to the square of half the line.

Page 30 - ... twice as many right angles as the figure has sides ; therefore all the angles of the figure together with four right angles, are equal to twice as many right angles as the figure has sides.

Page 9 - 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.

Page 22 - IF two triangles have two sides of the one equal to two sides of the other, each to each, but the angle contained by the two sides of one of them greater than the angle contained by the two sides equal to them, of the other ; the base of that which has the greater angle shall be greater than the base of the other...

Page 92 - If a straight line be divided into two equal, and also into two unequal parts, the squares on the two unequal parts are together double of the square on half the line and of the square on the line between the points of section. Let the straight line AB be divided into two equal parts...