Chapter 6 - 6.7 - Applications and Models - 6.7 Exercises - Page 494: 6

$A=65°$ $B=25°$ $C=90°$ $a=8.58$ $b=4$ $c=9.46$

$A+B+C=180°$ $A+25°+90°=180°$ $A=180°-25°-90°=65°$ $tan~A=\frac{opp}{adj}$ $tan~65°=\frac{a}{4}$ $a=4·tan~65°=8.58$ $cos~A=\frac{adj}{hyp}$ $cos~65°=\frac{4}{c}$ $c=\frac{4}{cos~65°}=9.46$