Question

Explanation needed

find the image of (1 2) after a reflection about y=-1 followed by a reflection about y=1

Answer 1

A‘‘ (1,6)

Explanation:

after a reflection about a horizontal line the x coordinates remain the same

the middle point of the segment AA’ lies on the line so it has y = -1

so we have

(y+y’)/2 = -1

y’ = -2 -y

y‘ = -2 -2 = -4

so A‘ (1,-4)

we can use the same reasoning to find the reflection about y = 1

x‘ = x

(y + y’)/2 = 1

y‘ = 2+4

y’ = 6

A‘‘(1,6)