Hi there! The answer is C.
The area of the square in the middle is the following:

Hence, the area of the square is 25 cm^2.
The area of one triangle is the following:

Hence, the total area of the four triangles is 4 × 20 = 80 cm^2.
Therefore, the total area of the pyramid is 80 + 25 = 105 cm^2. The answer is C.
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This expression is already simplified.
Answer:
19+19= x
So x, is 38. Just add 19 and 19