Answer:
To find the height of the box, we need to use the formula for volume of a box: Volume = length x breadth x height
Given the values for length and breadth, we can substitute them into the formula and solve for height: 140 = 7 x 5 x height
Simplifying the equation, we get: 140 = 35 x height
Dividing both sides by 35, we get: height = 4
Therefore, the height of the box is 4 cm