Answer:
D. diagonal = 20.10 cm
Explanation:
Find the bottom diagonal using the length and width.
diagonal² = 8² + 12²
diagonal = √64+144
diagonal = √208
diagonal = 4√13
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Find diagonal of the rectangular solid:
diagonal² = (4√13)² + 14²
diagonal² = 208 + 196
diagonal = √404
diagonal = 20.10 cm