Question

as an engineering technician, you need to estimate the elevation of a marker on a contour map. the distance between the 420 - foot and 440 - foot contours is 0.5 inch and the marker between them is 0.2 inch from the 420 - foot contour. what is the elevation of the marker, in feet?

a. 100
b. 424
c. 428
d. 430
e. 432

Explanation:

Step1: Calculate elevation change per inch

The elevation change between the 420 - foot and 440 - foot contours is $440 - 420=20$ feet, and the horizontal distance between them is 0.5 inch. So the elevation change per inch is $\frac{440 - 420}{0.5}=\frac{20}{0.5}=40$ feet per inch.

Step2: Calculate elevation of the marker

The marker is 0.2 inch from the 420 - foot contour. The elevation increase from the 420 - foot contour is $0.2\times40 = 8$ feet. So the elevation of the marker is $420+8 = 428$ feet.

Answer:

C. 428