## Elements of Geometry and Trigonometry |

### From inside the book

Results 1-5 of 25

Page 10

... Angles , like all other quantities , are susceptible of addition , subtraction , multiplication , and division ...

... Angles , like all other quantities , are susceptible of addition , subtraction , multiplication , and division ...

**right angle**; and the line AB is said to be perpendicular to CD . 11. Every angle BAC , less than a D**right angle**... Page 16

... angle ECB ( Ax . 3. ) . Scholium . The four angles formed about a point by two straight lines , which intersect each other , are together equal to

... angle ECB ( Ax . 3. ) . Scholium . The four angles formed about a point by two straight lines , which intersect each other , are together equal to

**four right angles**: for the sum of the two angles ACE , ECB , is equal to two right angles ... Page 27

...

...

**right angles**. In the same manner it may be proved that OGA + GOC is equal to two**right angles**. Cor . 1. If OGB is ...**four**acute angles are equal to each other , and so also are the**four**obtuse angles . PROPOSITION XXI . THEOREM ... Page 30

... angles of another , the third angles will also be equa , and the two triangles will be mutually equiangular . Cor . 3. In any triangle there can be but one

... angles of another , the third angles will also be equa , and the two triangles will be mutually equiangular . Cor . 3. In any triangle there can be but one

**right angle**...**four right angles**: hence , if all the angles of. 30 GEOMETRY . Page 31

...

...

**four**angles of a quadrilateral are asserted to be**right angles**, in the case of the rectangle and the square . Cor . 2. The sum of the angles of a pentagon is equal ... right angles , is equal to twice as many**right angles**BOOK I. 31.### Other editions - View all

### Common terms and phrases

adjacent adjacent angles altitude angle ACB angle BAC ar.-comp base multiplied bisect Book VII centre chord circ circumference circumscribed common cone convex surface Cosine cylinder diagonal diameter dicular distance divided draw drawn equally distant equations equivalent feet figure find the area formed four right angles frustum given angle given line gles greater homologous sides hypothenuse inscribed circle inscribed polygon intersection less Let ABC logarithm number of sides opposite parallelogram parallelopipedon pendicular perimeter perpen perpendicular perpendicular let fall plane MN polyedron polygon ABCDE PROBLEM proportional PROPOSITION pyramid quadrant quadrilateral quantities radii radius ratio rectangle regular polygon right angled triangle S-ABCDE Scholium secant segment similar Sine Cotang slant height solid angle solid described sphere spherical polygon spherical triangle square described straight line tang tangent THEOREM triangle ABC triangular prism vertex