Krishna
0

Step 1: By using the given data make a figure

            FORMULA:   \cos A = \frac{adjacent}{hypotenuse}

                                 \cos A = \frac{12}{13} (Given)

                           Therefore, Adjacent side = 12

                                             hypotenuse = 13

           CONSTRUCTION:

                        


Step 2: Find the unknown length.

               AC^2 = AB^2 + BC^2 (since Pythagoras theorem)

               13^2 = 12^2 + BC^2

               BC^2 = 169 - 144

               BC = \sqrt{25}

                        BC = 5


Step 3: Find the trigonometric ratios by plugging the relevant sides lengths.

            EXAMPLE: \sin A = \frac{opp}{hyp} =\frac{BC}{AC} = \frac{5}{13}

                   \tan A= \frac{opp}{adj} =\frac{BC}{AB} = \frac{5}{12}