...Proposition 2. Perpendicular to a Plane 37. Theorem. If a line is perpendicular to each of two intersecting lines at their point of intersection, it is perpendicular to the plane of the two lines. Given AO _L to OP and OR at O, and m, the plane of OP and OR. Prove that AO is _L to m. Proof. Through...

...meet, they intersect in a straight line. 2 . If a line is perpendicular to each of two intersecting lines at their point of intersection, it is perpendicular to the plane of the two lines. 3 . Every perpendicular to a given line at a given point lies in a plane perpendicular to the line...

...they intersect in a straight line, [1, cd] 2. If a line is perpendicular to each of two intersecting lines at their point of intersection it is perpendicular to the plane of the two lines. [2*, cd*] 3. Every perpendicular to a given line at a given point lies in a plane perpendicular to...

...every line lying in the plane and passing through its foot. Theorem. // a line is perpendicular to two lines at their point of intersection, it is perpendicular to the plane of the two lines. 2. Parallel planes. Definition. Two planes are parallel if they never meet. Theorem 1. Two non-parallel...

...point P (L2) . Now, L _L L. at P and L _L L2 at P. But, if a line is perpendicular to 2 intersecting lines at their point of intersection, it is perpendicular to the plane containing the 2 lines. Hence, L is perpendicular to the plane containing L^ and L2 at the point P....

...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 another. The projection of...