Answer: (-6, 5)
<u>Step-by-step explanation:</u>
Use the Midpoint Formula: 
Separate the x's and y's and solve them individually:

So, the k-coordinate is (-6, 5)
Postulate1:A line contains atleast 2 points.Postulate1a:A plane contains at least 3 points not all on one line.Postulate1b:Space contains atleast four points not all on one plane
5 feet is how far the ladder reaches
90 degrees
Hope this helps