Page:A Treatise on Electricity and Magnetism - Volume 2.djvu/327

Rh (2) For two lines (Fig. 42) of lengths $$a$$ and $$b$$ drawn perpendicular to the extremities of a line of length $$c$$ and on the same side of it.

(3) For two lines, $$PQ$$ and $$RS$$ (Fig. 43), whose directions intersect at $$O$$.

(4) For a point $$O$$ and a rectangle $$ABCD$$ (Fig. 44). Let $$OP$$, $$OQ$$, $$OR$$, $$OS$$, be perpendiculars on the sides, then