S.72 T.207

a) $Suorakulma$

$\alpha=\sin\alpha=\frac{10{,}4}{22{,}1}$
$\sin\alpha=28{,}07...\approx28{,}1$

$\beta=\sin\beta=\frac{19{,}5}{22{,}1}$
$\sin\beta=61{,}92...\approx61{,}9$

$V:\ \alpha\ on\ pienempi$

b)

$h=\sin40=\frac{x}{4}$

$x=\sin40\cdot4$
$x=2{,}571...\approx2{,}57\left(m\right)$
$A=\frac{6\cdot257}{2}=7{,}71\approx7{,}7\left(cm^2\right)$
$V:\ A\approx7{,}7cm^2$