Question

why is the distance between 2 successive contours indicate the slope of the land

Answer 1

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$\mathfrak{\blue{Answer.}}$Contour lines (thinner lines) between index contours are called intermediate contour lines. In the map shown below, the elevation difference between index lines is 100 meters. The elevation difference or vertical distance between two adjacent contour lines would be 20 meters (100 : 5 = 20).
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