A (-4, 3)
B(-4, 1)
C(-2, 1)
When you reflect about the y-axis, the coordinate becomes (-x, y)
A(-4, 3) ⇒ A' ( 4, 3)
B(-4, 1) ⇒ B' (4, 1)
C(-2, 1) ⇒ C' ( 2, 1)
To find the length of B'C', we will use the distance formula
[tex]|d|=\sqrt[]{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
x₁=4 y₁= 1 x₂=2 y₂=1
substitute the coordinates in the above
[tex]|d|=\sqrt[]{(2-4)^2+(1-1)^2}[/tex]
[tex]=\sqrt[]{(-2)^2+0}[/tex][tex]=\sqrt[]{4}[/tex]
[tex]=2[/tex]
Hence, the length is 2
