Page 38 - Ebook Trigonometri_Krisna Hasugian_MESP 2019
P. 38
Example 39 Find the length of AB. Round to the nearest tenth.
Since all three sides of the triangle are referred to and information about one
angle is given, we can use the Law of Cosines.
Since AB is opposite of <C, we will call it c and use the following formula,
² = ² + ² − 2 cos
² = 13² + 20² − 2(13)(20) cos 93°
= 596
2
= 14
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