Предмет: Математика, автор: sashagamer43

На рисунке изображены две книги. Длина меньшей книги равна 25 см, а её ширина 15 см. Определите примерную площадь большей книги в дециметрах квадратных (с точностью до целых).

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Ответы

Автор ответа: xxxeol
2
ДАНО
a = 25 см - длина
b = 15 см - ширина
НАЙТИ
S2 = ? - площадь большой книги.
РЕШЕНИЕ
Вычислим точнее, а потом округлим.
Рисунок к задаче в приложении.
Делаем на рисунке измерения сторон двух книг.
Получили (примерно) размеры на рисунке:
- у малой книги - 35*24 мм
 - у большой книги  - 60*44 мм.
Составим пропорции 
Х : 25 см = 60 : 35
Y : 15 см = 44 : 24
Решаем пропорции и получаем
Х = 25*60/35 ≈ 42,8 см
Y = 15* 44/24 ≈ 27.5 см
Находим площадь большой книги
S = X*Y = 42.8 * 27.5 = 1177 см² ≈ 12 дм² - площадь - ОТВЕТ
На втором рисунке  - совсем приблизительный расчет площади.
У малой книги примерно 4 дм², у большой - примерно 12 дм² - ОТВЕТ


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