Answer:
33.18208
Step-by-step explanation:
This can be solved via Law of Sines, but I´m gonna use sines for the sake of efficiency. :P
So, you have your 3 values and unknown length x.
First set up your proportions: [tex]\frac{sin(65)}{x}=\frac{sin(35)}{21}[/tex]
Cross multiply. [tex]x=\frac{21sin(65)}{sin(35)}[/tex]
Simplify. [tex]x=33.18208[/tex]