The distance between two points A=(x_1,y_1)A=(x1,y1) and B=(x_2,y_2)B=(x2,y2) is given by the distance formula.
D(A,B)=sqrt((x_2-x_1)^2+(y_2-y_1)^2)D(A,B)=√(x2−x1)2+(y2−y1)2
We are given
(x_1,y_1)=(-4,7)(x1,y1)=(−4,7)
and
(x_2,y_2)=(-7,8)(x2,y2)=(−7,8)
Plugging these values into the distance formula gives:
D(A,B)=sqrt((-7-(-4))^2+(8-7)^2)D(A,B)=√(−7−(−4))2+(8−7)2
D(A,B)=sqrt((-7+4)^2+(8-7)^2)D(A,B)=√(−7+4)2+(8−7)2
D(A,B)=sqrt((-3)^2+(1)^2)D(A,B)=√(−3)2+(1)2
D(A,B)=sqrt(9+1)D(A,B)=√9+1
D(A,B)=sqrt(10)~~3.1623D(A,B)=√10≈3.1623