the Law of Cosines (also called the Cosine Rule) says: c 2 = a 2 + b 2 − 2ab cos(C) It helps us solve some triangles. Let's see how to use it.

余弦定理，一般是指在欧氏平面的 三角形 中关于三边长度和一个角度 余弦 值的恒等式。 借助余弦定理，可以在已知三角形两边及其 夹角 的情况下，算出第三边的长度；也可以在已知三边长 …

Tutorial on the law of sines and cosines and on how to decide which formula to use in triangle problems.

In trigonometry, the law of cosines (also known as the cosine formula or cosine rule) relates the lengths of the sides of a triangle to the cosine of one of its angles. For a triangle with sides ⁠ ⁠, ⁠ ⁠, …

正弦定理是三角學中的重要工具，它適用於解決各種三角形相關的問題。 當我們已知一個三角形的任意兩邊長和其中一個夾角的大小時，可以利用正弦定理計算其他未知邊長或夾角的數值。 …

正弦定理（The Law of Sines）是三角学中的一个基本定理，它指出“在任意一个平面三角形中，各边和它所对角的正弦值的比相等且等于外接圆的直径”，即a/sinA = b/sinB =c/sinC = 2r=D（r …

It is possible to use trigonometry with non-right triangles using two laws: the sine law and the cosine law. The sine law is a ratio of sines and opposite sides. The law takes the following …

Trigonometry: Law of Sines, Law of Cosines, and Area of Triangles Formulas, notes, examples, and practice test (with solutions) Topics include finding angles and sides, the “ambiguous …

The law of sines relates the length of one side to the sine of its angle and the law of cosines relates the length of two sides of the triangle to their intermediate angle. Here, we will learn …

The laws of sines and cosines were first stated in this context, in a slightly different form than the laws for plane trigonometry. On a sphere, a great-circle lies in a plane passing through the …