 | University of St. Andrews - 1902 - 740 pages
...the mid-point of BC. AE cuts the diagonal BD in F. Prove that BF is £ BD. 11. If a straight line be at right angles to each of two straight lines at their point of intersection it shall be at right angles to the plane containing them. From a point P are drawn lines PA, PB perpendicular... | |
 | Euclid - Euclid's Elements - 1904 - 488 pages
...perp. to this plane. QED PROPOSITION 4. THEOREM. [Euclid-s Proof.] If a straight line is perpendicular to each of two straight lines at their point of intersection, it shall also be perpendicular to the plane in which they lie Let the st. line EF be perp. to each of... | |
 | 1907 - 798 pages
...the segments of 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,... | |
 | Great Britain. Board of Education - Education - 1912 - 1044 pages
...tothe ratio of the squares on corresponding sides. 9. Show that, if a straight line is perpendicular to each of two straight lines at their point of intersection, it is also perpendicular to the plane in which they lie. OXYZ is a tetrahedron such that OX = OY = OZ,... | |
 | Great Britain. Board of Education - Mathematics - 1912 - 632 pages
...the ratio of the squares on corresponding sides. 9. Show that, if a straight line is perpendicular to each of two straight lines at their point of intersection, it is also perpendicular to the plane in which they lie. OXYZis a tetrahedron such that OX = 0Y= OZ, and... | |
 | Education - 1914 - 914 pages
...and the diameter of the circle described about the triangle. 6. If a straight line is perpendicular to each of two straight lines at their point of intersection, it shall also be perpendicular to the plane in which they lie. 7. If a pyramid is cut by planes drawn... | |
 | Mathematics - 1871 - 280 pages
...are the middle points of the sides and A,B,C the intersections of opposite sides. EUCLID XI., &c. I. If a straight line stand at right angles to each of two straight lines at the point of their intersection, it shall also be at right angUs to the plane which passes through... | |
 | University of St. Andrews - 1900 - 670 pages
...How can the fourth point of a harmonic range be found, when three points of the range are given ? 6. If a straight line stand at right angles to each of two straight lines at the point of their intersection, it shall also be at right angles to their plane. The sum of the squares... | |
 | University of New Zealand - 1904 - 362 pages
...Through three points not collinear only one plane can be drawn. If a straight line be perpendicular to each of two straight lines at their point of intersection it is perpendicular to the plane passing through them. All normals to the same plane are parallel to one... | |
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If a straight line stand at right angles to each of two straight lines at the point of their intersection, it shall also be at right angles to the plane which passes through them, that is, to the plane in which they are. 
