Elementary Technical Mathematics

The angle in the degree is $B=24.1{}^\circ$.
Take the ${{\cos }^{-1}}$ to both sides of the equation, ${{\cos }^{-1}}\left( \cos B \right)={{\cos }^{-1}}\left( 0.9128 \right)$ The steps of the Ti-83 calculator are as follows Step1: Open Ti-83. Step2: Press $+$ button. Step3: Enter value like this, ${{\cos }^{-1}}\left( 0.9128 \right)=24.1047$ The obtained value is $24.1047$.