\(\displaystyle{\cos{{35}}}=\frac{{21}}{{x}}\)

\(\displaystyle{\cos{{35}}}={0.819}=\frac{{21}}{{x}}\)

\(\displaystyle{x}=\frac{{21}}{{0.819}}\)

\(\displaystyle{x}={25.64}\)

\(\displaystyle{\cos{{35}}}={0.819}=\frac{{21}}{{x}}\)

\(\displaystyle{x}=\frac{{21}}{{0.819}}\)

\(\displaystyle{x}={25.64}\)