Essential Skills Manual - Automotive Service Technician

ESSENTIAL SKILLS INVENTORY

Each different ratio has its own formula. These are shown below.

The ratio of opposite = sine or sin
hypotenuse

The ratio of adjacent = cosine or cos
hypotenuse

The ratio of opposite = tangent or tan
adjacent

NOTE

The acronyms for the three ratios are:

¾ Sine opposite hypotenuse – SOH

¾ Cosine adjacent hypotenuse – CAH

¾ Tangent opposite adjacent - TAS

These acronyms are extremely helpful as they can be used to write out the three
different formulas and aid in solving trigonometry questions. These three formulas
can be changed into three formula triangles and then it is a matter of substituting
them into the formula. The three formula triangles are shown in Figure 9.

Figure 9 – Formula triangles

To use the formula triangles, cover the unknown and complete the remaining
calculation. Each formula triangle can be used to construct three variations.

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