A water tank casts a shadow 21 m long. A tree of height 9.5 m casts a shadow 8 m long at the same time. The lengths of the shadows are directly proportional to their heights. Find the height of the tank.
The height of the tree = 9.5m
The shadow of the tree = 8m
According to the given condition in the question, the lengths of the shadow are in direct proportion.
∴
⇒ 
94