Books Books If a straight line is perpendicular to each of two straight lines at their point of intersection, it is perpendicular to the plane of those lines. Elements of Geometry: With Practical Applications to Mensuration - Page 170
by Benjamin Greenleaf - 1868 - 320 pages ## Plane and Solid Geometry

George Albert Wentworth - Geometry - 1904 - 496 pages
...SOLID GEOMETRY. PROPOSITION II. THEOREM. 507. If a straight line is perpendicular to each of two other straight lines at their point of intersection, it is perpendicular to the plane of the two lines. Let AB be perpendicular to BC and BD at B. To prove that AB is -L to the plane MN... ## Plane and Solid Geometry

Fletcher Durell - Geometry - 1911 - 553 pages
...different planes ? PROPOSITION I. THEOREM 509, If a straight line is perpendicular to each of tivo oilier straight lines at their point of intersection, it is perpendicular to the plane of those lines. Given AB JL lines BC and BD, and the plane MN passing through BC and BD. To prove AB... ## Solid Geometry

Fletcher Durell - Geometry, Solid - 1904 - 232 pages
...SOLID GEOMETRY V PROPOSITION I. THEOREM 509. If a straight line is perpendicular to each of two other straight lines at their point of intersection, it is perpendicular to the plane of those lines. Given AB _L lines BC and BD, and the plane MN passing through BC and BD. To prove AB... ## Treatise on Elementary Geometry

William Chauvenet - 1905 - 336 pages
...greater distance from the foot of the perpendicular. PROPOSITION IV.—THEOREM. 10. If a strait/hi line is perpendicular to each of two straight lines...of intersection, it is perpendicular to the plane of those lines. Let AP be perpendicular to PB and PC, at their intersection P; then .APIs perpendicular... ## The Elements of Solid Geometry

Charles Davison - Geometry, Solid - 1905 - 140 pages
...LINES PERPENDICULAR TO PLANES. 9. PROP. 8. If a straight line be perpendicular to each of two other straight lines at their point of intersection, it is perpendicular to the plane containing them*. Let OA be perpendicular to each of the lines OB, OC at their point of intersection... ## School Science and Mathematics, Volume 19

Education - 1919 - 924 pages
...subject, namely a model to illustrate the theorem: If a line is perpendicular to each of two other lines at their point of intersection it is perpendicular to the plane of the two lines. This model is made according to specifications, insuring uniformity, and I make a... ## School Science and Mathematics, Volume 19

Education - 1919 - 956 pages
...subject, namely a model to illustrate the theorem: If a line is perpendicular to each of two other lines at their point of intersection it is perpendicular to the plane of the two lines. This model is made according to specifications, insuring uniformity, and I make a... ## Examinations Papers

1907 - 796 pages
...the base and that contained by the sides of the triangle. 7. If a straight line be at right angles to each of two straight lines at their point of intersection, it is perpendicular to the plane in which they lie. AS and BC are two straight lines at right angles, and AP is a straight line at right angles... ## Mathematical Papers for Admission Into the Royal Military Academy and the ...

Royal Military Academy, Woolwich - Mathematics - 1909 - 444 pages
...spire being at the same level, determine the height of the spire. 7. Prove that a straight line which is perpendicular to each of two straight lines at their point of intersection is perpendicular to the plane containing them. 8 8. Prove that, if each of the edges of a tetrahedron... 