If a stair has 12 unit rises and a unit run of 10 inches, what is the total run?

To determine the total run of a stairway, you can use the formula that involves multiplying the unit run by the number of rises. In this case, the unit run is given as 10 inches, and there are 12 unit rises.

The total run can be calculated as follows:

Total Run = Number of Rises x Unit Run
Total Run = 12 (rises) x 10 (inches)
Total Run = 120 inches

In this context, the total run of 120 inches reflects the horizontal distance covered by the stairs. Each unit rise corresponds to a step, and each step collectively contributes to the total horizontal distance. The correct choice indicates the total linear distance along the ground that the staircase occupies, thus making it the relevant answer for this problem.