Tasha assembled a picture frame that is advertised as rectangular. The completed frame is 14 inches long and 10 inches wide. She measured the diagonal length across the frame as 20 inches. Which best explains why the frame cannot actually be rectangular?

For a rectangle, the length, width, and diagonal form a right triangle, so the Pythagorean theorem requires 14² + 10² = 20². But 14² + 10² = 196 + 100 = 296, while 20² = 400. Since these are not equal, the measurements cannot describe a rectangle; choice C states this mismatch.

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