Plane trigonometry, by S.L. Loney.

212

TRIGONOMETRY.

In the triangle APQ we have now determined the
sides AP and AQ; also the included angle PA Q (= a - 3)
is known. We can therefore find the side PQ by the
method of Art. 181.
If the four points A, B, P, and Q be not in the same
plane, we must, in addition, measure the angle PAQ; for
in this case PA Q is not equal to a - 3. In other respects
the solution will be the same as above.
195. Bearings and Points of the Compass. The
Bearing of a given point B as seen from a given point
0 is the direction in which B is seen from 0. Thus if
West by ~rth i < Eastb North
Bles~t' lNy SorUS~ East by i tb.
\ to tt tE S ot
4'r.**" V / I, ~E^
the direction of OB bisect the angle between East and
North, the bearing of B is said to be North-East
If a line is said to bear 20~ West of North we mean
that it is inclined to the North direction at an angle of
20~, this angle being measured from the North towards
the West.