Ex 6.5, 12
Two poles of heights 6 m and 11 m stand on a plane ground. If the distance between the feet of the poles is 12 m, find the distance between their tops.
Given: Height of first pole = AB = 6 m
Height of second pole = CD = 11 m
Distance b/w feet of poles = AC = 12 m
To Find :- Distance between the tops of the pole ,i.e., BD
Solution :-
Let we draw a line BE perpendicular to DC i.e. BE DC
Since AC is also perpendicular to DC as pole is vertical to ground,
So, BE = AC = 12 m
Similarly , AB = EC = 6 m
Now,
DE = DC EC
DE = 11 6
DE = 5 m
Since BED = 90 as BE DC
BED is right triangle
Using Pythagoras theorem in right angle triangle AEB
(Hypotenuse)2 = (Height)2 + (Base)2
(BD)2 = (DE)2 + (BE)2
(BD)2 = (5)2 + (12)2
(BD)2 = 25 + 144
(BD)2 = 169
BD = 169
BD = (13 13)
BD = ((13)2)
BD = 13
Hence, the distance between tops of the pole = 13 metre .

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.