## Elements of Geometry and Trigonometry |

### From inside the book

Page 11

The side

The side

**opposite**the right angle is called the hypothenuse . Thus , in the triangle ABC , right - angled at A , the side BC is the hypothenuse . B 17. Among the quadrilaterals , we distinguish : The square , which has its sides equal ... Page 15

... form one and the same straight line . PROPOSITION IV . THEOREM . When two straight lines intersect each other , the

... form one and the same straight line . PROPOSITION IV . THEOREM . When two straight lines intersect each other , the

**opposite**or vertical angles , which they form , are equal . Þ Let AB and DE be two straight A lines , BOOK I. 15. Page 16

Take away from both , the common angle ACE , there remains the angle ACD , equal to its

Take away from both , the common angle ACE , there remains the angle ACD , equal to its

**opposite**or vertical angle ECB ( Ax . 3. ) . Scholium . The four angles formed about a point by two straight lines , which intersect each other ... Page 20

It may be observed that the equal angles lie

It may be observed that the equal angles lie

**opposite**the equal sides : thus , the equal angles D and A , lie**opposite**the equal sides EF and BC . PROPOSITION XI . THEOREM . In an isosceles triangle , the angles**opposite**the ... Page 21

Conversely , if two angles of a triangle are equal , the sides

Conversely , if two angles of a triangle are equal , the sides

**opposite**them are also equal , and the triangle is isosceles . Let the angle ABC be equal to the angle ACB ; then will the side AC be equal to the side AB .### 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

ABCD adjacent altitude base become Book called centre chord circle circumference circumscribed common cone consequently contained Cosine Cotang cylinder described determine diameter difference distance divided draw drawn equal equations equivalent expressed extremities faces feet figure follows formed four frustum give given gles greater half hence homologous hypothenuse included inscribed intersection less let fall logarithm manner means measured meet middle multiplied number of sides opposite parallel parallelogram pass perpendicular plane polygon prism PROBLEM Prop proportional PROPOSITION pyramid quadrant quantities radii radius ratio reason rectangle regular remaining right angles Scholium segment sides similar Sine solid solid angle sphere spherical triangle square straight line suppose taken Tang tangent THEOREM third triangle triangle ABC unit vertex whole