Final answer:
An order of magnitude estimate for the size of a downtown skyscraper is typically 10² meters (Option B), as most skyscrapers range from about 100 to over 500 meters in height.
Step-by-step explanation:
The order of magnitude is used as a ballpark estimate to compare sizes or scales by powers of 10. For instance, a skyscraper downtown typically ranges in height from about 100 meters (for smaller, less prominent buildings) to over 500 meters for the tallest skyscrapers in the world. In terms of order of magnitude, this places the size of most downtown skyscrapers within 10² m (100 meters) to 10³ m (1,000 meters).
Taking a common tall skyscraper height, we might estimate it at around 200 meters high. Expressing this height as an order of magnitude, we see that it fits within the range of 10² meters. Thus, for an order of magnitude estimate for the size of a skyscraper downtown, the correct answer is B. 10²m.