Answer:
Approximate height of the silo is 18 feet.
Explanation:
By applying geometric mean theorem in the given right triangle ABC,

AD² = BD × CD
8² = 5 × (BC - BD) [Since, CD = BC - BD]
64 = 5(BC - 5)
BC - 5 =

BC - 5 = 12.8
BC = 17.8
BC ≈ 18 feet
Therefore. approximate height of the silo is 18 feet.