Solution:
Consider the distance between two planes = h m
It is given that
AD = 3125 m, ∠ACB = 600 and ∠ACD = 300
In triangle ACD
tan 300 = AD/AC
Substituting the values
1/√3 = 3125/AC
AC = 3125√3 ……. (1)
In triangle ABC
tan 600 = AB/AC
Substituting the values
√3 = (AD + DB)/ AC
So we get
√3 = (3125 + h)/ AC
AC = (3125 + h)/ √3 ….. (2)
Using both the equations
(3125 + h)/ √3 = 3125√3
By further calculation
h = (3125√3 × √3) – 3125
h = 3125 × 3 – 3125
h = 9375 – 3125
h = 6250 m
Therefore, the distance between two planes at the instant is 6250 m.