There are 12 such shapes. One can start with two squares, adding squares around the edge and rejecting shapes that have been previously seen. Repeating until you have 5 squares results in 12 distinct shapes.
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2 shapes are possible with 3 squares: L, I
5 shapes are possible with 4 squares: L, I, N, T, O
Answer: Choice B
12.5 < x < 18.9
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Explanation:
We have a triangle with these side lengths:
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