Question

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

Answer 1

It is super simple! y=40

Explanation:

Since the lines are perpendicular, all you have to do is set up the equation like 3y-30=90 then you just do basic algebra!

So

3y-30=90

+30 +30

3y=120

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3 3

y=40

Answer 2

There is a property that states that vertical angles are congruent with each other. By definition, vertical angles are opposite angles when two intersecting lines are drawn. From the figure, angle (3y - 30) is equal to angle (2x + 4). But first, let's determine x. One revolution is equal to 360°. So,

360 = 2(2x + 4) + 2(4x - 6)
Solving for x,
x = 91/3

Now, solving for y:
3y - 30 = 2x + 4
3y - 30 = 2(91/3) + 4
y = [2(91/3) + 4 + 30]/3
y = 31.56