L=2ПRα/ 360 = Rα=12*150=1800
A=15см
b=9см
P= 2(a+b)
P=2(15+9)
P=48см
<span>tgα</span><span>= </span><span>sinα</span><span>/</span><span>cosα</span><span>, </span><span>sin</span><span>^2 </span><span>α</span><span> + </span><span>cos</span><span>^2 α = 1, </span><span>sinα</span><span> = </span><em><span>√</span></em><span /><span>(1 – </span><span>cos</span><span>^2 α), </span><span>sinα</span><span> = </span><em><span>√</span></em><span /><span>(1 – 144/169) = </span><em><span>√</span></em><span /><span>25/169 = 5/13, </span><span>tgα</span><span> = 5/13|12/13 = 5/12.</span>
<span>Відповідь: tg</span><span>α = 5/12</span>
По т Пифагора найдем АВ= корень(АН:^2+ВН^2)= корень (24*24+7*7)=корень из 625=25 кос В= кос А т. к. треугольник АВС равнобедренный
кос А=кос В = НВ/АВ=7/25