Khoảng cách giữa hai điểm
A
A
1
(x
1
,y
1
)
và
A_2\left(x_2,y_2\right)
A
2
(x
2
,y
2
)
là:
A_1A_2=\sqrt{\left(x_1+x_2\right)^2+\left(y_1+y_2\right)^2}
A
1
A
2
=
(x
1
+x
2
)
2
+(y
1
+y
2
)
2
A_1A_2=\sqrt{\left(x_1-x_2\right)^2+\left(y_1-y_2\right)^2}
A
1
A
2
=
(x
1
−x
2
)
2
+(y
1
−y
2
)
2
A_1A_2=\sqrt{\left(x_1+x_2\right)^2}+\sqrt{\left(y_1+y_2\right)^2}
A
1
A
2
=
(x
1
+x
2
)
2
+
(y
1
+y
2
)
2
A_1A_2=\sqrt{\left(x_1-x_2\right)^2}+\sqrt{\left(y_1-y_2\right)^2}
A
1
A
2
=
(x
1
−x
2
)
2
+
(y
1
−y
2
)
2