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Chapter 3
Manual Calculations
In this chapter, we explore calculation features of this calculator, such as fraction to
decimal conversion and the quotient-reminder key, trigonometric calculation, as well
as basic arithmetic calculations.
1. Try it! 1
The speed of light is known to be 186,282
miles (approximately 300,000 kilometers) per
second. That means light can go around the
Earth 7 and a half times within a second!
Suppose you are standing at the equator.
While the Earth rotates over the period of one
day, you also rotate around the globe at a
certain speed. Knowing the facts above, can
you figure out how fast you are travelling, in
miles per hour?
Since distance travelled = average speed
×
time taken, the
following equation can be formed to find out the circumference of
the Earth (x miles):
x
×
7.5 = 186282
Then,
x = 186282
÷
7.5
Since you know the Earth turns around once a day (which means,
in 24 hours), divide the above “x” by 24 to get a value in miles per
hour.
24
×
v = x
v =
x
24