Thread: bearings

Not sure if I'm in the right forum as I'm new to this, but here goes.

I have a car traveling in a straight line from point C (-100,100) to point D (200,-100). I need to find the direction of travel as a bearing to the nearest degree. Any help?

slope diagram = -1
y-x/x+100= -1 simplifies to y= x

0,0 is the origin on a graph and the center 0f a 360 degree compass pointing true north. your course is 45 degrees W of north or 315 degrees true. Iwent the wrong way.change to 45 degrees south of east or135 degrees true

Originally Posted by sarahheath1985

Not sure if I'm in the right forum as I'm new to this, but here goes.
I have a car traveling in a straight line from point C (-100,100) to point D (200,-100). I need to find the direction of travel as a bearing to the nearest degree. Any help?

I do not understand reply #2.
The vector of direction is

Thus the direction angle is . You need to change that to degrees.

Yes Igoofed.the slope is -2/3 and angle = 33.7 and course is 33.7 degrees south of east or 123.7 degrees true

so,

what is the general formula? say the coordinates change to (-200,100) at C and (400,-200) at D?

There is no general formula. You are given two poimts on a coordinate grid. From these you determine the slope of the line connecting them.In this new case slope equals -1/2and angle equals arc tangent of -1/2= 26.6 deg. Coursefrom C to D is 26.6 deg south of east or 116.6 deg true

The "slope" of a line from to is the fraction and the angle the line makes with the x- axis is . However, that is measured counterclockwise from the x-axis while the "bearing" (as on a map) is measured clockwise from the y-axis ("north"). To convert to a "bearing", subtract 90 degrees and multiply by -1:
degrees.

The slope angle is always a positive acute angle. A sign is added only to show how it slants relative to the horizontal and does not apply to the angle itself.