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Two sides of a triangle and the angle opposite the shorter of them are given. What does this produce?
AOne possible triangle
BTwo possible triangles
CNo possible triangle
DFour possible triangles
Answer & Solution
Correct answer: B. Two possible triangles
1. Two sides and an interior angle have been given, so the sine rule is the tool to use.
2. The side opposite the given angle is the shorter of the two given sides.
3. In that situation two different triangles can be drawn on the same given dimensions.
4. This is called the ambiguous case, because the given information can be read in two ways.
5. The sine rule gives one angle, and a second angle with the same sine also fits.
6. Both of those answers are correct, so two possible triangles exist.
7. Answering one possible triangle misses the second angle with the same sine value.
8. Answering no possible triangle would need the given sides to be too short to close a triangle at all.
_Source: Siyavula Mathematics Grade 11 (Everything Maths, CC BY 4.0), Chapter 6: Trigonometry_
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