Of course, this formula can be derived, but we will leave this for you to do in the exercise (think about how the sine rule and cosine rule formulae were derived).

Exercise (please write answers to 3 significant figures)

Answers

1.) (a) 45cm², (b) 156cm², (c)52.6cm² (d) 69.3cm² (e) 27.6m², (f) 42.0 square miles

2.) (a) 72.3cm², (b) 28.6cm², (c) 33.1cm²

3.) (a) 31.3cm², (b) 470cm², (c) 50.1mm²

4.) (a) 8.51cm, (b) 6.96cm, (c) 3.97cm

5.) (a) 78.9º, (b) 31.6º, (c) 30º

Applied questions Answers

1.) (a) 12.7 cm² (b) 82.0 cm², (c) 367 cm²

2.) 26.9cm²

3.) 992 m²

4.) 37.1 cm²

5.) 36.9 cm²