Answer: Choice B
12.5 < x < 18.9
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Explanation:
We have a triangle with these side lengths:
- a = 10
- b = 16
- c = x = unknown
Let's assume that b = 16 is the largest side of this triangle.
By the converse of the pythagorean theorem, we need to be true in order for an acute triangle to happen.
So,
Now let's consider the possibility that the missing side x is actually the longest side.
Using the same theorem as before, we would say,
We found that x > 12.5 and x < 18.9
This is the same as saying 12.5 < x and x < 18.9
Put together, they form the approximate answer of 12.5 < x < 18.9