Find the area of a circle with radius 28 cm.
2 answers:
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Answer:
- There are two solutions:
- B = 58.7°, C = 82.3°, c = 6.6 cm
- B = 121.3°, C = 19.7°, c = 2.2 cm
Step-by-step explanation:
You are given a side and its opposite angle (a, A), so the Law of Sines can be used to solve the triangle. The side given is the shorter of the two given sides, so it is likely there are two solutions. (If the given side is the longer of the two, there will always be only one solution.)
The Law of Sines tells you ...
a/sin(A) = b/sin(B) = c/sin(C)
Of course, the sum of angles in a triangle is 180°, so once you find angle B, you can use that fact to find angle C, thus side c.
The solution process finds angle B first:
B = arcsin(b/a·sin(A)) . . . . . . or the supplement of this value
then angle C:
C = 180° -A -B = 141° -B
finally, side c:
c = a·sin(C)/sin(A)
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A triangle solver application for phone or tablet (or the one on your graphing calculator) can solve the triangle for you, or you can implement the above formulas in a spreadsheet (or even do them by hand). Of course, you need to pay attention to whether the functions involved give or take <em>radians</em> instead of <em>degrees</em>.
