An electrician has to repaired and electric fault on the pole of height 5 cm She needs to reach - Maths - Some Applications of Trigonometry

Question

An electrician has to repaired and electric fault on the pole of
height 5 cm She needs to reach a point 1 3 m below the top of the
pole to undertake the repair work (see figure) A
(a) What is the length of BD ?
b) What should be the length of Ladder, when inclined at an angle
of 60? to the harizontal ?
(c) How far from the foot of pole should she place the foot of the
ladder ?
(d) If the horizontal angle is changed to 30?, then what should be
the length of the ladder ?

Ankita Agarwal · Accepted Answer

Dear Student,

In Fig, the electrician is required to reach the point B on the pole AD
So, BD = AD-AB = 5-1 3m = 3
7 mHere, BC represents the ladder
 We need to find its length i e
 the hypotenuse of the right triangle BDCSo, BDBC= sin 60°3
7BC = 32Therefore, BC = 3
7×23 = 4 28 m approx,i e
 the length of the ladder should be 4
28 m
Now, DCBD = cot 60° = 13DC = 3
73 = 2 14 m approx
Therefore, she should place the foot of the ladder at a distance of 2
14 m from the pole
If the angle is changed to 30°Then, BDBC = sin 303
7BC = 12BC = 3 7×2BC = 7
4 m

Regards