## To find the depth of the water when the tank is in a horizontal position, we need to consider the dimensions and the change in orientation.

Let's break it down step by step:

1. The tank is initially tilted and resting on a 60 cm edge.

2. The water level reaches the midpoint of the base, which means it is positioned exactly halfway between the highest and lowest points.

3. The tank's length is 100 cm, width is 60 cm, and height is 40 cm.

To determine the depth of the water when the tank is horizontal, we need to consider the change in orientation. In this case, as we tilt the tank, the length becomes the height, the height becomes the depth, and the depth becomes the width.

Since the length of the tank is now the height of the water, and the height is 40 cm, the actual depth of the water is 40 cm when the tank is horizontal.

Therefore, the depth of the water in centimeters is 40 cm.