#1**+1 **

If we draw a perpendicular from D to CB....we will have a right triangle with a hypotenuse of 13 and a height DM (leg) of 12

So....call the intersection of this perpendicular and CB, M

So using the Pythagorean Theorem.....we can find CM as

CM = sqrt ( DC^2 - DM^2 ) = sqrt (13^2 - 12^2 ) = sqrt (169 - 144) = sqrt (25) = 5

So....M is the point (5, 0)......and it has the same x coordinate as D

CPhill Feb 9, 2019