Rectangular Coordinates & Bearings

Understanding Rectangular Coordinates

Rectangular coordinates are a way to pinpoint a location on a plane using two numbers. These numbers are called coordinates and are written as \$(x, y) \\$. Here's how they work:

• x-coordinate: This tells you how far along the horizontal axis (x-axis) the point is.
• y-coordinate: This tells you how far along the vertical axis (y-axis) the point is.

For example, the point \$(3, 4) \\$ is 3 units along the x-axis and 4 units up the y-axis.

Axes and Quadrants

The plane is divided into four quadrants by the x-axis and y-axis:

• Quadrant I: Both x and y are positive.
• Quadrant II: x is negative, y is positive.
• Quadrant III: Both x and y are negative.
• Quadrant IV: x is positive, y is negative.

Understanding Bearings

Bearings are used to describe direction. They are measured in degrees from the north in a clockwise direction. Bearings are always given as three-figure numbers.

• North is 000° or 360°.
• East is 090°.
• South is 180°.
• West is 270°.

For example, a bearing of 045° means 45 degrees clockwise from north.

Angles of Dip and Declination

In navigation, the angle of dip and declination are important:

• Angle of Dip: The angle at which the Earth's magnetic field lines enter the Earth. It varies with location.
• Angle of Declination: The angle between magnetic north and true north. It also varies depending on where you are.

Worked Example