A treatise on special or elementary geometry (1877)
Olney, Edward, 1827-1887, Olney, Edward, 1827-1887. Elements of trigonometry, plane and spherical · New York : Sheldon · leaf 239
then is the plane SVTU a tangentplane at P, and perpendicular to the radiusOP. For, a tangent (as ST) to the arc mP isperpendicular to the radius of the circle, i. e.yto OP, and also a tangent (as VU) to the arc aPis perpendicular to the radius of this circle,i.e., to OP. Hence, OP is perpendicular… … OF SPHERICAL TRIANGLES. 219 For, OP, the perpendicular, is shorter than any line which can be drawnfrom 0 to any other point in the plane (?), hence any other point in the planethan P lies farther from the centre of the sphere than the length of the radius,and is, therefore, without the sphere.…
Geometry · Trigonometry
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