Distance between two points (x1, y1), (x2,y2) is given by the formula
sqrt( (x1-x2)^2 + (y1-y2)^2). In our case this becomes
sqrt( (0-0)^2 + (12 -3)^2 ) =
sqrt( 9^2) =
9.
Solution 2:
Note points D and E both have x = 0 so segment DE is a vertical segment. The length is simply the difference of the y coordinates: 12- 3 = 9 as before.
