Distance formula help

The distance formula is    

d = √ [ (x₂ - x₁)^2 + (y₂ - y₁)^2 ]  

Let (6, -7) , (4, 4)  = (x₁,y₁)  (x₂, y₂)     so we have

d = √ [ (4 - 6)^2 + ( 4 - (-7) ) ^2 ]   =   √ [ (-2)^2 + (11)^2 ]  = √ [4 + 121 ]   = √ 125   =  √[25 * 5]  =  5√5 ≈  11.1803