Example 1

Use trigonometry to find the hypotenuse in the triangle below. You have been given the opposite side and the angle. 


Remember: 

Sine = Opposite ÷ Hypotenuse

Cosine = Adjacent  ÷ Hypotenuse

Tangent = Opposite  ÷ Adjacent 





Cover up the information you have, and the information you are trying to find in the working triangles below. 


              


Use sine because there are three circles in the sine triangle. 


Now that you have decided to use the sine ratio, you can use this working triangle to work out the hypotenuse. 


Cover up the H because you are trying to find the hypotenuse. 


This means that you have to divide the opposite by the sine of 17° 

Hyp = Opp ÷ sin 17°

        = 9m ÷ 0.292

        = 30.822m