[tex] \displaystyle \large \tt{ \sin a = \frac{opposite}{hypotenuse} }[/tex]
First, we have to focus on ∠a, at the angle a or ∠a, the opposite is z because ∠a is the opposite side of z.
The hypotenuse side is always x, even if we change from ∠a to ∠b (b = 90°-a)
So what we have now are:
- opposite = z (Refer to the bold text)
- hypotenuse = x (hypotenuse is always the side that is opposed to a right angle.)
Substitute the letter in the ratio:
[tex] \displaystyle \large \boxed{ \sin a = \frac{z}{x} }[/tex]
