Can somebody explain how to do it?

Hello from MrBillDoesMath!

9

Discussion:

Solution 1:

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.

Thank you,

MrB

x+14

step-by-step explanation:

step-by-step explanation: