Sin Cos Tan

Sin Cos Tan

1. Sin = SOH

   • Opposite/Hypotenuse

2. Cos = CAH

   • Adjacent/Hypotenuse

3. Tan = TOA

   • Opposite/Adjacent

4. Using Trig. to find Angles

   • Label the sides we know
     • Choose Sin, Cos or Tan depending on the sides we know
       • In this case COS, as we have the HYP - 13 and the ADJ -12
         • COS(angle) = ADJ/HYP = 12/13
         • Look up the angle using the [shift] button on the calculator
           • angle= COS^-1(12/13)
             • 22.6
       • In this case SIN, as we have the OPP - 15 and the HYP -20
         • SIN(angle) = OPP/HYP = 15/20
         • angle= SIN^-1(15/20)
           • 48.6

5. Using Trig. to find Missing edges

   • Label the Triangle that we know, or are trying to find
     • Choose SIN, COS or TAN depending on the edge we are interested in.
       • Choose the correct formula and write down the calculation
         • Type into Calculator

6. Trigonometry gives us a method for finding missing edges in right angled triangles when we know one edge and one angle (in addition to the right angle). We can also use trig. to find an angle if we know the edges.