Высота треугольника 7см основание большемеё на 3см найдите площадь​

ответ:

35

объяснение:

s треугольника = h (высота) * а (основание) * 0.5

а = 7 + 3 = 10

s = 7 * 10 * 0.5 = 35

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углы ромба    можно найти из формулы его  площади.

s=a²*sin  α, где а- стороны ромба,   α - угол между ними     

sin  α=s: a² 

  площадь ромба авсд равна   удвоенной площади   его половины-∆ авд.

полупериметр авсд= p=(9+9+3): 2=10,5

площадь 2-х ∆ авд по ф. герона:

  s=2*√(10,5*1,5*1,5*3)=4,5√35

sin  ∠вад=(4,5√35): 9²=0,3286, 

что по т. брадиса соответствует углу 19º11’

сумма углов ромба, прилежащих к одной стороне, равна 180º, 

следовательно, второй   угол равен 180º-19º11’=160º49'