## The Elements of Euclid: The Errors, by which Theon, Or Others, Have Long Ago Vitiated These Books, are Corrected and Some of Euclid's Demonstrations are Restored. Also, to this Second Edition is Added the Book of Euclid's Data. In Like Manner Corrected. viz. the first six books, together with the eleventh and twelfth |

### From inside the book

Results 1-5 of 5

Page 198

To draw a straight line

A be the given point above the plane BH ; it is required to draw from the point A a

straight line

To draw a straight line

**perpendicular**to a plane , from a given point above it . LetA be the given point above the plane BH ; it is required to draw from the point A a

straight line

**perpendicular**to the plane BH . In the plane draw any straight line ... Page 199

it . therefore GH is

right angles to ...

it . therefore GH is

**perpendicular**to AF , and consequently AF is Book XI .**perpendicular**to GH . and AF is**perpendicular**to DE ; therefore AF is**perpendicular**to each of the straight lines GH , DE . but if a straight line stands atright angles to ...

Page 201

From the point B draw BG

through DE , EF , and let it meet that plane in G ; and through G draw GH parallel

b to ED , and GK parallel to EF . and b . 31.1 . because BG is

...

From the point B draw BG

**perpendicular**to the plane which a . 11. II . passesthrough DE , EF , and let it meet that plane in G ; and through G draw GH parallel

b to ED , and GK parallel to EF . and b . 31.1 . because BG is

**perpendicular**to the...

Page 204

CE the common section of the planes , has been proved to be

the other plane CK ; therefore the plane DE is at right angles to the plane CK . In

like manner , it may be proved that all the planes which pass through AB are at ...

CE the common section of the planes , has been proved to be

**perpendicular**tothe other plane CK ; therefore the plane DE is at right angles to the plane CK . In

like manner , it may be proved that all the planes which pass through AB are at ...

Page 423

equal to the alternate angle FNL , that is to the angle FEL in the same segment ,

therefore the triangle NEF is similar to LEF . and in the segment EGF there can be

no other triangle upon the base EF which has the ratio of its

equal to the alternate angle FNL , that is to the angle FEL in the same segment ,

therefore the triangle NEF is similar to LEF . and in the segment EGF there can be

no other triangle upon the base EF which has the ratio of its

**perpendicular**to ...### What people are saying - Write a review

We haven't found any reviews in the usual places.

### Other editions - View all

### Common terms and phrases

added alſo altitude angle ABC angle BAC baſe BC is given becauſe Book Book XI caſe circle circle ABCD circumference common cone cylinder Definition demonſtrated deſcribed diameter divided double draw drawn equal equal angles equiangular equimultiples exceſs fame fides firſt folid fore four fourth given angle given in poſition given in ſpecies given magnitude given ratio given ſtraight line greater Greek half join leſs likewiſe magnitude manner meet muſt oppoſite parallel parallelogram perpendicular plane priſm produced PROP proportionals Propoſition pyramid reaſon rectangle remaining right angles ſame ſecond ſegment ſhall ſhewn ſides ſimilar ſolid ſquare ſquare of AC taken THEOR theſe third thro triangle ABC wherefore whole

### Popular passages

Page 5 - Let it be granted that a straight line may be drawn from any one point to any other point.

Page 163 - 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.

Page 48 - 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 73 - The straight line drawn at right angles to the diameter of a circle, from the extremity of it, falls without the circle; and no straight line can be drawn from the extremity between that straight line and the circumference, so as not to cut the circle...

Page 105 - 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. either the sides adjacent to the equal...

Page 3 - A circle is a plane figure contained by one line, which is called the circumference, and is such that all straight lines drawn from a certain point within the figure to the circumference, are equal to one another.

Page 167 - Similar triangles are to one another in the duplicate ratio of their homologous sides.

Page 54 - AB be the given straight line ; it is required to divide it into two parts, so that the rectangle contained by the whole, and one of the parts, shall be equal to the square of the other part.

Page 47 - 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 37 - To describe a parallelogram that shall be equal to a given triangle, and have one of its angles equal to a given rectilineal angle.