The second type of triangle is one where the lengths of the three sides are known, Figure 13.10. This method for determining the area of a triangle is easier to use because the only measurements are the three sides of the triangle. The shape of the triangle doesn't influence the difficulty in completing the measurements.
The primary limitation of this method is the requirement of measuring the length of all three sides. This method cannot be used if one or more of the side lengths cannot be measured. The equation for area is:
A = VS(S - a)(S - b)(S - c) S = 2 where a, b, and c are the lengths of the three sides.
Problem: Determine the area (ft2) for a triangle having sides measuring 650.0 ft, 428.0 ft, and 282.0 ft.
A = 7680.0 (680.0 - 650.0) (680.0 - 428.0) (680.0 - 282.0)
= 45,233.15598 or 45,230 ft2
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