15.2.3 Trigonometry, PT3 Focus Practice


Question 10:
A technician needs to climb a ladder to repair a street lamp as shown in Diagram below.
(a) What is the length, in m, of the ladder?
(b) Find the height, in m, of the lamp post.

Solution:


(a)

cos 70 o = 1 h h= 1 cos 70 o h= 1 0.342 h=2.924 m Hence, the length of the ladder =2.924 m

(b)
tan 70 o = T 1 T=tan 70 o ×1    =2.747×1    =2.747 m The height of the lamp post =2.747+1.2 =3.947 m


Leave a Comment