Let us assume shape of well is like a solid right circular cylinder

Radius of cylinder, r = 3.5/2 = 1.75m

Depth of well, h = 16m

Volume of right circular cylinder, V’ = π r² h

---------(I)

Given that, length of platform, l = 27.5 cm

Breadth of the platform, b = 7cm

Let height of the platform be x m

Volume of the rectangle, V’’ = lbh

= 27.5 × 7 × x

= 192.5x -----------(II)

Since well is spread evenly to form the platform, so volume V’ = V’’

⇒ x = 0.8m

∴ Height of the platform = 80cm