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}