| University of St. Andrews - 1902
...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 - 456 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
...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 - 1032 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
...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 - 912 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
...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 - 360 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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