Topological maps also have scales, but in this case the scale is a ratio representing
the measure on a map to some number of the actual units of measure on the Earth’s
surface. For example, a map with a scale of 1:25,000 means that one inch on the map
is equal to 25,000 inches on the ground. Because both numbers have the same units,
it can also be interpreted as any unit measure. For example, the same map could also
be interpreted as 1 centimeter equals 25,000 centimeters on the ground, or 1 meter
equals 25,000 meters, and so on. For those who prefer to measure in miles and kilo-
meters, most topographic maps also offer a graphic scale in the legend. (For more
about scales, see “Math in Engineering.”)
What is a currency exchange rate?
When traveling to another country, it is important to know the currency exchange
rate, which is the value of a traveler’s home currency compared to the currency of the
country being visited. For example, like all currency, the U.S. dollar fluctuates daily
when compared to other countries’ currencies. If you travel to Canada, and the U.S.
dollar can buy $1.40 Canadian dollars, then the exchange rate is 1.40 to 1. If you go to
New Zealand, and the U.S. dollar exchange rate is 0.5477, then 1 New Zealand dollar is
worth 54.77 U.S. cents.
What are some non-Hindu-Arabic numeralsencountered around the world?
Although Hindu-Arabic numerals are the dominant numerals used around the world,
there are some places in which other number symbols are used. For example, there
are Chinese, Japanese (kanji), Greek, Thai, and Hebrew numerals. The illustration lists
some of the ones encountered by world travelers (for more information about num-
bers, see “Math Basics.”)