2.1

216

$\tan54°=\frac{x}{22m}$
$x=22\tan54°$
$x=30{,}2804...m$
$\tan41°=\frac{y}{22m}$
$y=22\tan41°$
$y=19{,}1243...m$
$h=x-y=11{,}156...m\approx11m$

212

a)
$\alpha=\gamma-\beta$

$\tan\beta=\frac{10}{72}\parallel\tan^{-1}$

$\beta=7{,}907...°$
$\tan\gamma=\frac{20}{72}\parallel\tan^{-1}$
$\gamma=15{,}524...°$
$\alpha=7{,}617...°\approx7{,}6°$
b)
$\tan\alpha=\frac{x}{10{,}0}$
$\cos25{,}0°=\frac{x}{5{,}2}$
$x=5{,}2\cos25°$
$x=4{,}7128...cm$
$\tan\alpha=\frac{4{,}712...}{10{,}0}\parallel\tan^{-1}$
$\alpha=25{,}233...°\approx25{,}2°$

215

$\sin25°=\frac{x}{11900m}$
$x=11900\sin25°$
$x=5029{,}15...m\approx5029m$

210

$A=ah$
$a=320m$

$\sin40°=\frac{h}{150}$

$h=150\sin40°$
$h=96{,}4181...m$
$A=320m\cdot96{,}4181...m=30853{,}80...m^2\approx3{,}1ha$

211

a) tosi
b) epätosi
c) tosi
d) epätosi
e) tosi

202

a)
$\sin\alpha=\frac{28}{41}\parallel\sin^{-1}$
$\alpha=43{,}072°\approx43{,}1°$
b)
$\cos\alpha=\frac{105}{135}\parallel\cos^{-1}$
$\alpha=38{,}942...°\approx38{,}9°$

201

a)
$\tan27°=\frac{x}{8{,}4}$
$x=8{,}4\tan27°$
$x=4{,}280...cm\approx4{,}3cm$
b)
$\cos50°=\frac{x}{58}$
$x=58\cos50°$
$x=37{,}2816...cm\approx37cm$

207

a)
$\cos\alpha=\frac{19{,}5}{22{,}1}\parallel\cos^{-1}$
$\alpha=28{,}0724..°\approx28{,}1°$
b)

$A=\frac{ah}{2}$

$\tan40°=\frac{h}{3{,}0}$
$h=3\tan40°$
$h=2{,}5172...cm$

$A=\frac{6{,}0\cdot2{,}5172...}{2}=7{,}55189...cm^2\approx7{,}6cm^2$

206

a) kolmion saa jaettua kahteen yhtäsuureen suorakulmaiseen kolmioon koska se on tasakylkinen
$\cos\alpha=\frac{12{,}0}{17{,}0}\parallel\cos^{-1}$
$\alpha=45{,}0991...°\approx45{,}1°$
b)
$\sin\alpha=\frac{40}{45}\sin^{-1}$
$\alpha=62{,}7339...°\approx62{,}7°$