The diagram shows a field ABC.
AC = 240 m
Use the sine rule to calculate AB.

Answer:
AB ≈ 312.1 m
Step-by-step explanation:
Using the Sine rule in the triangle, then
[tex]\frac{AB}{sin85}[/tex] = [tex]\frac{240}{sin50}[/tex] ( cross- multiply )
AB × sin50° = 240 × sin85° ( divide both sides by sin50° )
AB = [tex]\frac{240sin85}{sin50}[/tex] ≈ 312.1 m ( to 1 dec. place )