Let us first draw a right ΔABC.
Now, we know that tan A = \(\frac{BC}{AB} = \frac{3}{4}\)
Therefore, if BC = 4k, then AB = 3k, where k is a positive number.
Now, by using the pythagoras theorem, we have
AC2 = AB2 + BC2
= (4k)2 + (3k)2 = 25 k2
AC = 5k
So,
Now, we can write all the trigonometric ratios using their definitions.