What is the slope of the grade if a topographic map indicates 10 contours over 200 feet with a contour interval of 2 feet?

To determine the slope of the grade based on the information provided, it's important to understand how to calculate the slope using contours on a topographic map.

In this case, the topographic map has 10 contours, and each contour represents a change in elevation of 2 feet. Therefore, the total vertical change in elevation can be calculated as:

Total Elevation Change = Number of Contours × Contour Interval

Total Elevation Change = 10 × 2 feet = 20 feet

The horizontal distance covered by these contours is given as 200 feet. With this information, the slope can be calculated using the formula:

Slope = Vertical Change / Horizontal Distance

Slope = 20 feet / 200 feet = 0.1

To express this slope in a form typically used in construction, it can be converted into a ratio format, which represents the horizontal distance for every unit of vertical rise.

To convert it to ratio terms:

0.1 can be expressed as 1:10. This means for every 10 feet of horizontal distance, there is a 1-foot vertical rise.

When the ratio is flipped to represent the horizontal distance per vertical rise, it can be stated as 10:1. This indicates