Table of contents
- 0. Review of College Algebra4h 43m
- 1. Measuring Angles39m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
7. Non-Right Triangles
Law of Cosines
8:44 minutes
Problem 35c
Textbook Question
Textbook QuestionIn Exercises 35–36, the three given points are the vertices of a triangle. Solve each triangle, rounding lengths of sides to the nearest tenth and angle measures to the nearest degree. A(0, 0), B(-3, 4), C(3, -1)
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Distance Formula
The distance formula is used to calculate the length of a side of a triangle given two points in a Cartesian plane. It is derived from the Pythagorean theorem and is expressed as d = √((x2 - x1)² + (y2 - y1)²). This formula is essential for determining the lengths of the sides of the triangle formed by the given vertices A, B, and C.
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Quadratic Formula
Law of Cosines
The Law of Cosines relates the lengths of the sides of a triangle to the cosine of one of its angles. It is particularly useful for finding unknown angles when the lengths of all three sides are known. The formula is c² = a² + b² - 2ab * cos(C), where a, b, and c are the sides of the triangle, and C is the angle opposite side c. This concept is crucial for solving the triangle after determining the side lengths.
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Angle Measures in Triangles
Understanding angle measures in triangles is fundamental in trigonometry. The sum of the interior angles of any triangle is always 180 degrees. Once the lengths of the sides are calculated, the angles can be found using the Law of Sines or the Law of Cosines, allowing for a complete solution of the triangle. Rounding the angle measures to the nearest degree is often required for clarity and precision.
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