CAIE IGCSE Mathematics Elevation and Depression Angles

Practise constructing the right triangle from horizontal sight lines and calculating an angle of elevation or depression to one decimal place.

Exam points

identify the angle of elevation above the observer's horizontal or depression below it
subtract observer or platform heights before forming the vertical side of the right triangle
apply inverse tangent to vertical change ÷ horizontal distance and round the angle as required

[Maximum number: 3]

NOT TO SCALE

The diagram shows triangle ABC on horizontal ground.
$A C=15 \mathrm{~m}, B C=8 \mathrm{~m}$ and $A B=20 \mathrm{~m}$ .
BP and CQ are vertical poles of different heights.
$B P=3 \mathrm{~m}$ and $C Q=4 \mathrm{~m}$ .
AQ and PQ are straight wires.

Calculate the angle of elevation of Q from P.

7.1 or 7.13 or 7.125 to 7.126
M2 for $\tan P=\frac{4-3}{8}$ oe or M1 for vertical line =4-3

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E6.2.4 Carry out calculations involving angles of elevation and depression question 1