Answer:
I thank its b not sure sorry if its wrong
Answer:
10.5.
Step-by-step explanation:
By similar triangles:
IJ / 21 = 8 /(8+8) = 1/2
IJ / 21 = 1/2
IJ = 1/2 * 21
= 10.5.
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Explanation:</h2><h2 />
The complete question is shown in the figure below. As you can see one square units is well shown in the graph. So we can conclude that the distance between two consecutive points is 1 unit. If so, then we can calculate the area of the parallelogram as follows:

Then, finding CB by Pythagorean Theorem:

And:

Therefore:

I think the answer is B) The mean of the 5th and 6th values