On a topographic map, two contour lines are at elevations 130 ft and 140 ft, with a contour interval of 50 ft. What is the percentage slope?

On a topographic map, two contour lines are at elevations 130 ft and 140 ft, with a contour interval of 50 ft. What is the percentage slope?

• A. 10%
• B. 20%
• C. 30%
• D. 40%

Answer: (B)

To calculate the percentage slope between two contour lines, you need to determine the vertical rise and the horizontal distance, and then use these values to find the slope as a percentage. In this scenario, the difference in elevation between the two contour lines is 140 ft - 130 ft = 10 ft. This is the vertical rise. The contour interval mentioned is 50 ft, which suggests that every contour line represents an elevation difference of 50 ft on the map. However, the question focuses on the actual elevation differences indicated by the contour lines. The formula for percentage slope is: \[ \text{Percentage Slope} = \left( \frac{\text{Vertical Rise}}{\text{Horizontal Distance}} \right) \times 100 \] Though the horizontal distance is not provided directly, in typical cases, the percentage slope can also be simplified to focus on the vertical rise in relation to a standard horizontal distance. If we assume that the horizontal distance between the two contour lines for this calculation is 100 ft, which is common for easier computations, the slope would be calculated as follows: \[ \text{Percentage Slope} = \left( \frac{10 \text{ ft}}{100 \

To calculate the percentage slope between two contour lines, you need to determine the vertical rise and the horizontal distance, and then use these values to find the slope as a percentage.

In this scenario, the difference in elevation between the two contour lines is 140 ft - 130 ft = 10 ft. This is the vertical rise. The contour interval mentioned is 50 ft, which suggests that every contour line represents an elevation difference of 50 ft on the map. However, the question focuses on the actual elevation differences indicated by the contour lines.

The formula for percentage slope is:

[

\text{Percentage Slope} = \left( \frac{\text{Vertical Rise}}{\text{Horizontal Distance}} \right) \times 100

]

Though the horizontal distance is not provided directly, in typical cases, the percentage slope can also be simplified to focus on the vertical rise in relation to a standard horizontal distance. If we assume that the horizontal distance between the two contour lines for this calculation is 100 ft, which is common for easier computations, the slope would be calculated as follows:

[

\text{Percentage Slope} = \left( \frac{10 \text{ ft}}{100 \