Hart, C. A. (Clara Avis), b. 1863, Feldman, Daniel D., b. 1872 · New York, American Book Co · leaf 341
he plane containing a straight line and its projectionupon a plane is perpendicular to the given plane. Ex. 1215. If two planes are perpendicular to each other, a line per-pendicular to one of them from any point in the other lies in the otherplane. 330 SOLID GEOMETRY Propositiox XXIY. Theorem 681.… … Given planes FQ aud RS _L plane MN and intersecting eachother in line AB. To prove : I. That AB intersects plane MN^.II. AB ± plane MN. I. Argument 1. Let planes PQ and RS intersect plane m:N in lines PD and RE, respectively. 2. Then PD and RE intersect in a point as C. 3. .-. AB passes through C;…
Geometry, Plane · Geometry, Solid
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