Trigonometric Determination of Area
If you know all three sides of a triangle, you
can determine the area by applying the following
formula:
Where s = 1/2 perimeter of a triangle
For the triangle shown in figure 1-30, the area
computation is
When you know two sides of a triangle and
the angle included between them, you can
determine the area by applying, appropriately, one
of the following formulas:
In figure 1-31, two sides, b = 13.00 ft and
c = 9.00 ft, and the included angle, A = 40°00´,
are given. The sine of 40°00´ is 0.64279. The area
computation is as follows:
Figure 1-31.-Area of a triangle with two sides and one angle
Figure 1-32.-Scientific pocket calculator.
SCIENTIFIC POCKET
CALCULATOR
Figure 1-32 illustrates a typical pocket
calculator that replaces the slide rule, logarithm
tables, and office adding machine. This tool,
packed with the latest in state-of-the-art solid-state
technology, is a great asset for our trade. With
it we can handle many problems quickly and
accurately without having to hassle with lengthy,
tedious computations. This tool should serve us
faithfully for a long time if we treat it with respect
and care.
Today’s hand-held calculators have become
an everyday part of our lives. Rugged and
inexpensive, they’re a practical answer to the real
need we all have for quick, accurate calculations.
THE KEYBOARD
Your calculator has many features to make
calculations easy and accurate. To allow you to
use all of these features without crowding the
keyboard, the designer has caused some of the
keys to have more than one function. If you look
closely at the keyboard, you’ll notice that the keys
in the column on the left side have two function
symbols. These keys are called dual-function keys
because they perform two functions. If you want
given.
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