10.3 Angles of Elevation and Depression, Paper 1 (Short Questions)


Question 1:
Diagram below shows two vertical poles on a horizontal plane. J, K, L, M and N are five points on the poles such that KL = MN.
Name the angle of elevation of point J from point M.
 
Solution:

Angle of elevation of point J from point M = ∠KMJ

Question 2:
Diagram below shows two vertical poles JM and KL, on a horizontal plane.
The angle of depression of vertex K from vertex J is 42o.
Calculate the angle of elevation of vertex K from M.

Solution:
JN = 10 tan 42o = 9.004 m
NM = 25 – 9.004 = 15.996 m
KL = NM = 15.996 m
tan K M L = K L M L = 15.996 10 = 1.5996 K M L = tan 1 1.5996 = 57 o 59


Question 3:
Diagram below shows a vertical pole KMN on a horizontal plane. The angle of elevation of from L is 20o.
Calculate the height, in m, of the pole.

Solution:
tan 20 o = K M K L 0.3640 = K M 15 K M = 5.4 m Height of the pole = 9 + 5.4 = 14.4 m

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