Предмет: Алгебра, автор: ЛужицаЧая

Стороны прямоугольника относятся как 7:3 Определи стороны прямоугольника, если его площадь равна 84cm2
Помогите, пожалуйста! Очень нужно!

Ответы

Автор ответа: Олеся9006

Пусть длина 7х, то ширина 3х. Площадь 7х*3х=84 21х^2=84 х^2=4 x=2. 2*7=14 см длина, 2*3=6 см ширина. (Х^2-это Х в квадрате)

Автор ответа: kirichekov

пусть х коэффициент пропорциональности, х>0.
тогда стороны прямоугольника
а =7х
b =3x
S =a*b
уравнение:
84= 7х*3х
21х^2=84
х^2=4
х1=-2, -2<0
х2=2
а=7*2, а=14
b=3*2, b=6
ответ: стороны прямоугольника 14 см и 6 см

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