translated
so the distance from A to A' should be the same as form B to B'
distance formula
distance between (x1,y1) and (x2,y2) is
[tex]D=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
so distance between (1,5) and (-2,1) is
[tex]D=\sqrt{(-2-1)^2+(1-5)^2}[/tex]
[tex]D=\sqrt{(-3)^2+(-4)^2}[/tex]
[tex]D=\sqrt{9+16}[/tex]
[tex]D=\sqrt{25}[/tex]
[tex]D=5[/tex]
the distance is 5 units
