If the temperature centigrade increases by 10 degrees, by how much does the temperature Fahrenheit increase?

It’s easy to get tangled in the full conversion formula, but the key to this puzzle lies in the different sizes of the degrees on each scale. Both the Celsius and Fahrenheit scales were defined by the freezing and boiling points of water. For Celsius, this range is a neat 100 degrees (from 0 to 100). For Fahrenheit, however, that same physical change from freezing to boiling water spans a much larger 180 degrees (from 32 to 212).

Because the Fahrenheit scale packs 180 degrees into the same temperature range that the Celsius scale covers in just 100, each Fahrenheit degree represents a smaller change in temperature. The ratio between them is 180 to 100, which simplifies to 1.8. This means that for every one-degree increase on the Celsius scale, the Fahrenheit scale must increase by 1.8 degrees to keep up.

Therefore, when the temperature in centigrade rises by 10 degrees, you simply multiply that change by the 1.8 ratio. This gives you a corresponding increase of 18 degrees on the Fahrenheit scale. This relationship holds true for any temperature change, whether it's a summer heatwave or a winter cold snap.