On a topographical map with contour lines at 130 feet and 140 feet, what is the percentage of the slope given a contour interval of 50 feet?

On a topographical map with contour lines at 130 feet and 140 feet, what is the percentage of the slope given a contour interval of 50 feet?

• A. 10%
• B. 20%
• C. 25%
• D. 30%

Answer: (B)

To determine the percentage of the slope between the two contour lines at 130 feet and 140 feet, you first need to identify the vertical rise and the horizontal distance based on the contour interval and the provided elevations. The vertical rise between the two contour lines is calculated as the difference in elevation: 140 feet - 130 feet, which equals 10 feet. The slope percentage is calculated by taking the vertical rise, dividing it by the horizontal distance (which can be conceptualized in terms of the contour interval), and then multiplying by 100 to convert it to a percentage. In this case, the slope percentage formula is: \[ \text{Percentage of slope} = \left( \frac{\text{Vertical rise}}{\text{Horizontal distance}} \right) \times 100 \] Assuming a standard horizontal distance representation based on a common ratio for the contour interval, the horizontal distance can be taken as the contour interval of 50 feet. This will give us: \[ \text{Percentage of slope} = \left( \frac{10 \text{ feet}}{50 \text{ feet}} \right) \times 100 = 20\% \] This calculation shows that the percentage of

To determine the percentage of the slope between the two contour lines at 130 feet and 140 feet, you first need to identify the vertical rise and the horizontal distance based on the contour interval and the provided elevations.

The vertical rise between the two contour lines is calculated as the difference in elevation: 140 feet - 130 feet, which equals 10 feet. The slope percentage is calculated by taking the vertical rise, dividing it by the horizontal distance (which can be conceptualized in terms of the contour interval), and then multiplying by 100 to convert it to a percentage.

In this case, the slope percentage formula is:

[

\text{Percentage of slope} = \left( \frac{\text{Vertical rise}}{\text{Horizontal distance}} \right) \times 100

]

Assuming a standard horizontal distance representation based on a common ratio for the contour interval, the horizontal distance can be taken as the contour interval of 50 feet. This will give us:

[

\text{Percentage of slope} = \left( \frac{10 \text{ feet}}{50 \text{ feet}} \right) \times 100 = 20%

]

This calculation shows that the percentage of