Question

In the figure, point k is the image of point j under a reflection across line L. Find y

Answer 1

Since, point K is the image of point J under a reflection across line L.

The distance, JM = MK

Hence, 2x + 4 = 4x - 6
4x - 2x = 4 + 6
2x = 10
x = 5

Also refrection of a point across a line form an angle of 90 degrees at the point of refrection.
i.e. 3y - 30 = 90
3y = 90 + 30 = 120
y = 120 / 3 = 40

Therefore, the value of y is 40.