If the grade is 2% and the vertical rise is 18 inches, what is the horizontal distance?

To determine the horizontal distance based on the given grade and vertical rise, understanding the relationship between these variables is essential. The grade is defined as the ratio of vertical rise to horizontal run, expressed as a percentage.

In this case, a grade of 2% means for every 100 units of horizontal distance, the vertical rise is 2 units. Given that the vertical rise is 18 inches, the relationship can be set up using the formula:

Grade (%) = (Vertical Rise / Horizontal Distance) * 100

Using this information:

• First, convert the vertical rise into feet to make calculations simpler. Since 18 inches is equivalent to 1.5 feet (18 inches ÷ 12 inches/foot).

• Plugging in the values into the formula gives:

2 = (1.5 / Horizontal Distance) * 100.

To solve for horizontal distance, rearranging the formula gives:

Horizontal Distance = (1.5 / 2) * 100.

Calculating this yields:

Horizontal Distance = 0.75 * 100 = 75 feet.

Thus, the horizontal distance required to achieve a vertical rise of 18 inches at a grade of 2% is indeed 75 feet. Therefore, B is