Law of Cosines Worksheet
Practice applying the Law of Cosines to solve for unknown sides and angles in triangles.
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Law of Cosines Practice
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Read each question carefully and use the Law of Cosines to solve for the missing side or angle. Show all your work.
1. In triangle ABC, find the length of side 'a' if b = 10, c = 12, and angle A = 60°.
2. In triangle XYZ, find the measure of angle X if x = 7, y = 11, and z = 13.
3. Which formula represents the Law of Cosines to find side 'b'?
b² = a² + c² - 2ac sin(B)
b² = a² + c² - 2ac cos(B)
b/sin(B) = a/sin(A)
b² = a² + c² + 2ac cos(B)
4. The Law of Cosines is used to solve for missing sides or angles in triangles.
5. When you know all three sides of a triangle, you can use the Law of Cosines to find any .
6. The Law of Cosines can be used in both right and non-right triangles.
True
False
7. A triangular plot of land has sides measuring 200 meters, 300 meters, and 400 meters. Find the measure of the largest angle in the plot.