Look at the figure if tan x=3/y and cos x =y/z what is the value of sin x?

Recall:

The tan of the measure of an angle is the ratio of the opposite side to the adjacent side to that angle, that is :

. 

Since this ratio is 3/y, we denote the opposite side, and adjacent side respectively by 3 and y. 

(Technically we should write 3t and yt, but we try our luck as we see y in the second ratio too!)

Similarly, .

The adjacent side is already denoted by y, so we denote the length of the hypotenuse by z.

Now the sides of the right triangle are complete. 



A