The volume of a rectangular tank is given by the formula $V = lwh$, where $l$ is the length, $w$ is the width, and $h$ is the height.
We are given that the volume of the rectangular tank is 7000 m$^3$, the length is 25 m, and the width is 80 m.
Substituting these values into the formula for volume, we get $V = lwh = 25 \times 80 \times h = 7000$, so $h = \frac{7000}{25 \times 80} = 1.75m$.