ABSTRACT
At the end of this chapter, you should be able to:
• state and use the sine rule • state and use the cosine rule • use various formulae to determine the area of any triangle • apply the sine and cosine rules to solving practical trigonometric problems
To ‘solve a triangle’ means ‘to find the values of unknown sides and angles’. If a triangle is right-angled, trigonometric ratios and the theorem of Pythagoras∗ may be used for its solution, as shown in Chapter 38. However, for a non-right-angled triangle, trigonometric ratios and Pythagoras’ theorem cannot be used.
