Bearings - Corbettmaths

Summary

This video provides an in-depth explanation of bearings, which are the directions of travel measured clockwise from north. It covers how to determine bearings in various scenarios, such as calculating the bearing between two locations or showing a location when given a bearing and distance. The video demonstrates practical examples with diagrams, showcasing techniques for measuring bearings using protractors and scales. The key takeaway is the importance of using three-figure bearings, ensuring accuracy in navigation and calculations, and understanding how to apply these concepts in real-world situations.

Takeaways

• 😀 Bearings represent the direction of travel, measured clockwise from north.
• 😀 Bearings are expressed as three-digit numbers, even if the angle is less than 100 degrees (e.g., 060 degrees).
• 😀 North is always considered the starting point for measuring bearings, with the angle increasing clockwise.
• 😀 If the bearing is less than 100 degrees, a zero is added in front to ensure a three-figure bearing (e.g., 044 degrees).
• 😀 To calculate a bearing between two locations, first draw a north line from the starting point.
• 😀 Use a protractor to measure the angle clockwise from the north line to the direction of travel.
• 😀 Bearings can be calculated using a reflex angle (greater than 180 degrees) or by measuring the acute angle and subtracting from 360 degrees.
• 😀 In some questions, a scale is provided (e.g., 1 cm = 200 meters) to calculate actual distances between locations.
• 😀 The bearing of a location can be used to place it on a map when provided with the correct distance and bearing.
• 😀 A 360-degree protractor can be helpful for directly reading off the bearing for reflex angles.

Q & A

What is a bearing in navigation?

A bearing is the direction of travel, measured clockwise from north. It is expressed in degrees, and bearings are typically given as three figures (e.g., 090, 180, 270).

How do you find the bearing between two locations?

To find the bearing between two locations, draw a north line from the starting point, then measure the angle clockwise from north to the line connecting the two points using a protractor.

What is the significance of three-figure bearings?

Bearings are always expressed as three figures. If the bearing is less than 100 degrees, a zero is added in front (e.g., 060 degrees instead of 60 degrees).

How do you measure the bearing of Belfast from Antrim in the given example?

To measure the bearing of Belfast from Antrim, draw a north line at Antrim, then use a protractor to measure the angle clockwise from north to the line joining Antrim and Belfast. In the example, the bearing is 104 degrees.

What should you do if the bearing is a reflex angle (greater than 180 degrees)?

If the bearing is a reflex angle, you can either measure the acute angle and subtract it from 360 degrees or measure the obtuse angle and add it to 180 degrees to get the total bearing.

How do you convert distances on a map using a scale?

To convert distances on a map, use the scale provided in the question. For example, if one centimeter on the map represents 200 meters in real life, and the distance on the map is 6 centimeters, multiply 200 by 6 to get the actual distance of 1200 meters.

What is the bearing of Castletown from Milton in the second example?

In the second example, the bearing of Castletown from Milton is 044 degrees. To find this, a protractor is used to measure the clockwise angle from the north line at Milton to the line connecting Milton and Castletown.

How do you handle bearings when using a scale to find locations?

When using a scale, the bearing helps determine the direction, while the distance is found by measuring the length on the map and applying the scale. For example, if a location is 30 kilometers away and the scale shows 1 cm = 5 km, you would mark 6 centimeters on the map.

What are the different methods for measuring a reflex angle bearing?

You can measure a reflex angle bearing in two main ways: by measuring the acute angle and subtracting it from 360 degrees, or by measuring the obtuse angle and adding it to 180 degrees.

How do you measure the bearing from the shop to the house on the island?

To measure the bearing from the shop to the house, draw a north line at the shop, then use a protractor to measure the angle clockwise from north to the line connecting the shop and the house. In the example, the bearing is 117 degrees.