[b]Introduction to the Sine Rule Materi[/b][br]The sine rule is an equation that expresses the relationship between three angles and three sides in any triangle. The purpose of using the sine rule is to find the lengths of the sides of a triangle in any triangle. Or it can also be used to find out the size of the angles of an unknown triangle.[br]

In ∆ACR:[br]  [img width=200,height=31]https://idschool.net/wp-content/ql-cache/quicklatex.com-eb896ade38db0a01c6557adc0ad656c6_l3.svg[/img][br]In ∆BCR:[br]  [img width=203,height=31]https://idschool.net/wp-content/ql-cache/quicklatex.com-8e537064af8a42d83dbc00cc3db52b9b_l3.svg[/img][br]Based on the two equations above, it can be concluded that[br]  [img width=64,height=11]https://idschool.net/wp-content/ql-cache/quicklatex.com-4e361d88cede5a4dae81591c8f08d1c1_l3.svg[/img][br]  [img width=125,height=11]https://idschool.net/wp-content/ql-cache/quicklatex.com-b8743b3d7522c1fec7c9f6e3e269954a_l3.svg[/img][br]  [img width=95,height=31]https://idschool.net/wp-content/ql-cache/quicklatex.com-f03fd5d52e4e3e5448c57d29435edbba_l3.svg[/img][br]A sine rule is obtained which expresses the relationship between the lengths of the sides and angles of a triangle. In a similar way, the equation of the sine rule will be obtained as given in the equation below.[br]

The function of the sine rule above can be used to determine the length of an unknown side of a triangle. In addition, it can also be used to find the size of the angles of an unknown triangle.[br][br]To increase your understanding of idschool friends, an example question will be given which is equipped with a discussion on using the sine rule to determine the length of one of the unknown sides of a triangle.