## Elements of Geometry |

### From inside the book

Results 1-5 of 19

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**Oblique**, and Parallel**Lines**. THEOREM . 27. ALL right angles are equal . Demonstration . Let the straight**line**CD be perpendicular to Fig . 16. AB ( fig . 16 ) , and GH to EF , the angles ACD , EGH , will be equal . Take the four ... Page 5

... lines , which have two points common , coin- cide throughout , and form one and the same straight line . Demonstration . Let the two points , which are common to the two lines , be A and B ( fig . 19 ) . In the first ...

... lines , which have two points common , coin- cide throughout , and form one and the same straight line . Demonstration . Let the two points , which are common to the two lines , be A and B ( fig . 19 ) . In the first ...

**Oblique Lines**. 5. Page 7

... lines BA and CA , can only be at their intersection A ; therefore the two triangles ABC , Fig . 23 . Fig . 24 . Fig . Of Perpendicular and

... lines BA and CA , can only be at their intersection A ; therefore the two triangles ABC , Fig . 23 . Fig . 24 . Fig . Of Perpendicular and

**Oblique Lines**. 7. Page 9

... line AD from the vertex A to the point D , the middle of the base BC ; the two triangles ABD , ADC , will have the three sides of the one equal to the three sides of the other , each to each , namely , AD common to both ...

... line AD from the vertex A to the point D , the middle of the base BC ; the two triangles ABD , ADC , will have the three sides of the one equal to the three sides of the other , each to each , namely , AD common to both ...

**Oblique Lines**. 9. Page 11

... lines ACF , ABF , might be drawn between the same two points A and F , which is impossible ( 25 ) ; it is , then , equally impossible to draw two perpendiculars from the same point to the same straight line . 51 ...

... lines ACF , ABF , might be drawn between the same two points A and F , which is impossible ( 25 ) ; it is , then , equally impossible to draw two perpendiculars from the same point to the same straight line . 51 ...

**Oblique Lines**. 11.### Other editions - View all

### Common terms and phrases

ABC fig adjacent angles altitude angle ACB angle BAC base ABCD bisect centre chord circ circular sector circumference circumscribed common cone consequently construction convex surface Corollary cube cylinder Demonstration diagonals diameter draw drawn equal angles equiangular equilateral equivalent faces figure formed four right angles frustum GEOM given point gles greater hence homologous sides hypothenuse inclination intersection isosceles triangle JOHN CRERAR LIBRARY join less Let ABC let fall line AC mean proportional measure the half meet multiplied number of sides oblique lines opposite parallelogram parallelopiped perimeter perpendicular plane MN polyedron prism produced proposition radii radius ratio rectangle regular polygon right angles Scholium sector segment semicircle semicircumference side BC similar solid angle sphere spherical polygons spherical triangle square described straight line tangent THEOREM three angles triangle ABC triangular prism triangular pyramids vertex vertices whence