How do you find the significant figure of 505kg-450.25kg

4 significant figures

Explanation:

505 has 3 significant figures

450.25 has 5 significant figures

First do simple subtraction

505 - 450.25 =54.75

And then evaluate any number that has significance or is important if the decimal were to be moved.

4 significant figures

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation: