TO DRAW A RIGHT LINE BETWEEN TWO GIVEN POINTS._The Elements of Perspective arranged for the use of schools and intended to be read in connection with the first three books of Euclid

[Illustration: Fig. 6.]

Let _AB_, Fig. 6., be the given right line, joining the given points _A_

and _B_.

Let the direct, lateral, and vertical distances of the point _A_ be

_TD_, _DC_, and _CA_.

Let the direct, lateral, and vertical distances of the point _B_ be

_TD′_, _DC′_, and _C′B_.

Then, by Problem I., the position of the point _A_ on the plane of the

picture is _a_.

And similarly, the position of the point _B_ on the plane of the picture

is _b_.

Join _ab_.

Then _ab_ is the line required.

The Elements of Perspective arranged for the use of schools and intended to be read in connection with the first three books of Euclid · 第 12 / 91 题