Revision NotesExam QuestionsFlashcardsPast PapersMock Exams
IBMathsDPAnalysis & Approaches (AA)SLRevision Notes3. Geometry & TrigonometryTrigonometryAngles of Elevation & Depression

Angles of Elevation & Depression (DP IB Analysis & Approaches (AA)): Revision Note

Amber

Written by: Amber

Reviewed by: Dan Finlay

Updated on

DP Analysis & Approaches (AA): SLDP Analysis & Approaches (AA): HLDP Applications & Interpretation (AI): HLDP Applications & Interpretation (AI): SLDP Applications & Interpretation (AI): HLDP Applications & Interpretation (AI): SLDP Analysis & Approaches (AA): HLDP Analysis & Approaches (AA): SL

Did this video help you?

Elevation & Depression

What are angles of elevation and depression?

  • Angles of elevations or depressions are formed when a person looks at an object

    • It is an angle of elevation if the person looks up

    • It is an angle of depression if the person looks down

  • The angle is formed between

    • the horizontal line from the person's eyes

    • the line of sight from the person's eyes to the object

Diagram of a person observing a bird and a boat, illustrating angles of elevation and depression relative to the horizontal line of sight.
Example of an angle of elevation and an angle of depression

  • Right-angled trigonometry can be used to find

    • an angle of elevation or depression

    • or a missing distance

Examiner Tips and Tricks

The tangent ratio is the most commonly used ratio in questions involving angles of elevation and depression.

Worked Example

A cliff is perpendicular to the sea and the top of the cliff stands 24 m above the level of the sea. The angle of depression from the cliff to a boat at sea is 35°. At a point xm up the cliff is a flag marker and the angle of elevation from the boat to the flag marker is 18°.

a) Draw and label a diagram to show the top of the cliff, T, the foot of the cliff, F, the flag marker, M, and the boat, B, labelling all the angles and distances given above.

 

3-3-3-ai-sl-elevation--depression-we-solution-i

b) Find the distance from the boat to the foot of the cliff.

3-3-3-ai-sl-elevation--depression-we-solution-ii

c) Find the value of x.

3-3-3-ai-sl-elevation--depression-we-solution-iii

You've read 0 of your 5 free revision notes this week

Unlock more, it's free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

    Test yourself

    Did this page help you?

    Previous:Sine Rule, Cosine Rule & Area of a TriangleNext:Bearings & Constructions
    Author
    Reviewer
    Amber

    Author: Amber

    Expertise: Maths Content Creator

    Amber gained a first class degree in Mathematics & Meteorology from the University of Reading before training to become a teacher. She is passionate about teaching, having spent 8 years teaching GCSE and A Level Mathematics both in the UK and internationally. Amber loves creating bright and informative resources to help students reach their potential.

    Dan Finlay

    Reviewer: Dan Finlay

    Expertise: Maths Subject Lead

    Dan graduated from the University of Oxford with a First class degree in mathematics. As well as teaching maths for over 8 years, Dan has marked a range of exams for Edexcel, tutored students and taught A Level Accounting. Dan has a keen interest in statistics and probability and their real-life applications.