The Law of Sines or Sine Rule is very useful for solving triangles. According to the law a sin A b sin B c sin C d displaystyle frac a sin A frac b sin B frac c sin Cd. In order to use sine rule one side and the angle opposite must be known as well as one other length or angle.
And 2 the sine formulas have sin-sin and cos-cos.
The Law of Sines. Sin Aa Sin Bb Sin Cc In this case the fraction is interchanged. For right angle triangles we can use Pythagoras and SOHCAHTOA to find missing. The law of sine is defined as the ratio of the length of sides of a triangle to the sine of the opposite angle of a triangle.