General Mathematics WAEC

Bearings

Aperçu

Overview:

In General Mathematics, the topic of Bearings delves into the precise way of expressing direction or location of one point in relation to another. Bearings are essential in navigation, surveying, and various real-life applications that require accurate orientation information. The concept of bearings involves understanding angles in a compass direction starting from the north direction and rotating clockwise.

One of the primary objectives of studying bearings is to comprehend the concept of angles of elevation and depression. Angles of elevation are the angles formed above the horizontal line when looking up at an object, while angles of depression are the angles formed below the horizontal line when looking down at an object. These angles play a crucial role in determining the bearing of one point from another accurately.

Calculating distances and angles using bearings is another key aspect covered in this topic. By applying trigonometric ratios of sine, cosine, and tangent of angles, students learn how to determine distances between points and angles with precision. Tables of trigonometric ratios, especially for standard angles like 30 degrees, 45 degrees, and 60 degrees, are instrumental in these calculations.

Moreover, the utilization of sine and cosine rules aid in solving complex problems related to bearings. These rules allow for finding missing sides or angles in triangles when the information provided is limited. Graphs of trigonometric ratios further enhance the understanding of how these ratios behave across different angles, facilitating visual interpretation and problem-solving skills.

Real-life applications of bearings extend to scenarios like determining the height of objects or structures, calculating distances between points in maps or landscapes, and establishing the direction of one point relative to another. Whether it is calculating the bearing of an aircraft, locating a hidden treasure based on given bearings, or surveying lands accurately, the knowledge of bearings and trigonometry is indispensable.

By mastering the concept of bearings and its applications, students not only enhance their mathematical skills but also develop a practical understanding of how mathematics is intricately intertwined with everyday navigation and spatial orientation. The ability to interpret bearings, calculate distances, and angles using trigonometric principles equips individuals with essential problem-solving tools that can be applied in diverse scenarios.

Objectifs

  1. Solve real-life problems involving bearings
  2. Apply trigonometric ratios in bearings problems
  3. Understand the concept of bearings
  4. Calculate distances and angles using bearings
  5. Determine bearings of one point from another

Note de cours

Bearings are a way of describing the direction one point is from another using angles. They are commonly used in navigation to find the direction from one place to another. Understanding bearings is crucial in solving real-life problems related to distance and direction.

Évaluation de la leçon

Félicitations, vous avez terminé la leçon sur Bearings. Maintenant que vous avez exploré le concepts et idées clés, il est temps de mettre vos connaissances à lépreuve. Cette section propose une variété de pratiques des questions conçues pour renforcer votre compréhension et vous aider à évaluer votre compréhension de la matière.

Vous rencontrerez un mélange de types de questions, y compris des questions à choix multiple, des questions à réponse courte et des questions de rédaction. Chaque question est soigneusement conçue pour évaluer différents aspects de vos connaissances et de vos compétences en pensée critique.

Utilisez cette section d'évaluation comme une occasion de renforcer votre compréhension du sujet et d'identifier les domaines où vous pourriez avoir besoin d'étudier davantage. Ne soyez pas découragé par les défis que vous rencontrez ; considérez-les plutôt comme des opportunités de croissance et d'amélioration.

  1. Find the bearing of point B from point A if A is located at coordinates (2,4) and B is located at coordinates (6,8). A. N45°E B. S45°W C. S45°E D. N45°W Answer: A. N45°E
  2. Find the distance between points P(3, 5) and Q(9, 3). A. 2 units B. 6 units C. 8 units D. 10 units Answer: C. 8 units
  3. If the bearing of X from Y is N30°E, what is the bearing of Y from X? A. S60°W B. S30°W C. N60°W D. N30°W Answer: D. N30°W
  4. Point A is 10 km directly north of point B. What is the bearing of point B from point A? A. S90°E B. S90°W C. N90°W D. N90°E Answer: B. S90°W
  5. A tree is located at a bearing of N40°E from a point P, and a tower is located at a bearing of S50°E from the same point P. What is the difference in the angle between the tree and the tower? A. 10° B. 90° C. 100° D. 140° Answer: A. 10°
  6. Given that the bearing of Y from X is N60°W, what is the bearing of X from Y? A. S30°E B. S60°E C. N30°E D. N60°E Answer: D. N60°E
  7. If the bearing of a ship from a lighthouse is N45°E and the lighthouse is directly north of the ship, what is the direction of the ship from the lighthouse? A. East B. West C. North D. South Answer: A. East
  8. A plane is flying on a bearing of N60°E. If the wind is blowing towards N, what is the true bearing of the plane's direction? A. N60°E B. N60°W C. S30°E D. S30°W Answer: D. S30°W
  9. Given that the bearing of point R from point Q is S50°W and the bearing of point S from Q is N40°E, what is the difference in the bearings of R and S from Q? A. 10° B. 50° C. 90° D. 180° Answer: A. 10°
  10. If the bearing of point T from point U is S40°E and the bearing of point V from U is N60°W, what is the bearing of V from T? A. N20°W B. S80°W C. N20°E D. S80°E Answer: D. S80°E

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Questions de révision

Vous vous demandez à quoi ressemblent les questions passées sur ce sujet ? Voici plusieurs questions sur Bearings des années précédentes.

NECO SSCE - General Mathematics - 2005

Question 1 Rapport

A ship sails 6km from a port on a bearing 070° and then 8km on a bearing of 040°. Find the distance from the port.
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JAMB UTME - Mathematics - 2025

Question 1 Rapport

A bird flies from a tree P on a bearing of N60º E to a building, Q, a distance of  200 km. It then changes course and flies to another tree R on a bearing of S30ºE. Tree R is directly east of tree P. Calculate the distance of the building to tree R.

Détails de la réponse

Bearing is a way of describing direction using angles measured clockwise from north. For example, N60ºE means 60° east of north, and S30ºE means 30° east of south.


Step 1: Drawing and understanding the path
Let’s clarify the problem with a diagram (you can imagine or sketch this):

  • P is the starting tree.
  • The bird flies from P to Q (the building) on a bearing of N60ºE, meaning the direction is 60º east of north.
  • After reaching Q, it turns and flies toward R (another tree), on a bearing of S30ºE (30º east of south). You are told R is directly east of P.

Step 2: Finding coordinates using trigonometry
Let's place P at the origin \((0,0)\). The bird's first flight to Q covers 200 km at an angle of 60º east of north. In trigonometry, the north direction matches the positive y-axis, and east is the positive x-axis.


To find the coordinates of Q:

  • East (x-component): \( 200 \times \sin(60^\circ) \)
  • North (y-component): \( 200 \times \cos(60^\circ) \)

Since \( \sin(60^\circ) = \frac{\sqrt{3}}{2} \) and \( \cos(60^\circ) = \frac{1}{2} \), the position of Q is:

  • x-coordinate: \( 200 \times \frac{\sqrt{3}}{2} = 100\sqrt{3} \)
  • y-coordinate: \( 200 \times \frac{1}{2} = 100 \)

So, Q is at \((100\sqrt{3}, 100)\).


Step 3: Coordinates of R
Tree R is directly east of P. Since P is at \((0,0)\), R must be at \((x, 0)\) for some x.


The bird flies from Q to R on a bearing of S30ºE. Bearing S30ºE is 30° east of due south, which means the angle is 30° to the east from the negative y-axis. In terms of vector components from Q to R:

  • East (x-component): \( d \times \sin(30^\circ) = d \times \frac{1}{2} \)
  • South (y-component): \( -d \times \cos(30^\circ) = -d \times \frac{\sqrt{3}}{2} \) (negative, because south is in the negative y direction)

Setting up the coordinates of R: \[ x_R = 100\sqrt{3} + \frac{d}{2} \] \[ y_R = 100 - d \frac{\sqrt{3}}{2} \] But since R is directly east of P, \( y_R = 0 \). So: \[ 100 - d \frac{\sqrt{3}}{2} = 0 \] Solving for \( d \): \[ d \frac{\sqrt{3}}{2} = 100 \] \[ d = \frac{200}{\sqrt{3}} \]


Conclusion
The distance from the building (Q) to tree R is therefore \(\frac{200}{\sqrt{3}}\) km. This value matches the correct answer in the options.


Underlying concept: The question uses bearings, vector components, and trigonometry to find positions and distances in navigation problems. Recognizing which trigonometric functions to use based on the angle and direction is key to solving these types of problems.

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WAEC SSCE - General Mathematics - 1996

Question 1 Rapport

If x is a real number which of the following is more illustrated on the number line?

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