Using the Sine Rule to find missing angles

Task goals

• Identify the side opposite each labelled angle.
• Select a complete known side-angle pair before substituting into the Sine Rule.
• Rearrange the Sine Rule to make the sine of the missing angle the subject.
• Use inverse sine to calculate an acute missing angle.
• Use the angle sum of a triangle to calculate a remaining angle where needed.
• Round only the final answer and check that the angle size is reasonable for its opposite side.