Предмет: Геометрия, автор: liliannakramberi

В треугольнике ABC отрезок DE с концами на сторонах AB и BC параллелен к стороне AC. $S_{\triangle DBE}$ = 4 см², $S_{ADEC}$ = 5 см², $DE$ = 7 см. Найти длину AC.
А) 9,5 см
Б) $9\frac{2}{3}$ см
В) 12 см
Г) 10,5 см
Д) 9 см

Приложения:

liliannakramberi: Можно пожалуйста объяснение еще пожалуйста!!!!

volna7: По трем углам. Угол А равен углу D.

orjabinina: Это избыточные данные, их можно не учитывать для признака подобия

Ответы

Автор ответа: Klick

Ответ: Г

Объяснение:

$\triangle DBE \sim \triangle ABC\\k^2=\dfrac{S_{ABC}}{S_{DBE}}=\dfrac{9}{4} \Rightarrow k=\dfrac32\\k=\dfrac{AC}{DE} \Leftrightarrow AC=k\cdot DE=\dfrac32 \cdot 7=10.5$

liliannakramberi: Спасибо вам большое!!!! А откуда взялось 9?

volna7: 4 + 5 = 9 см^2 - площадь треугольника АВС.

liliannakramberi: Теперь понял спасибо!!!!

mathkot: Абсолютно верно

Автор ответа: irinan2014

Ответ:

Объяснение:

Это ответ Г).

Приложения:

sunbeamm: Помогите с геометрией пожалуйста вопрос в профиле

Предыдущий вопрос

Следующий вопрос

Интересные вопросы

Предмет: Английский язык, автор: екатерина149

помогите пожалуйста
зарание спасибо

2 года назад

Предмет: Английский язык, автор: alyakhapakhi

помогите перевести текст
A Jobclub is a place, where long term unemployed people work at finding a job in a professional and systematic way by adopting a businesslike approach. The first Job clubs, developed from work done in North America, were opened in 1984. They proved popular and successful and the service expanded rapidly. Job clubs take a bold and positive stance: there is a job available for each member. Aim: to provide people who are unemployed for 26 weeks or more with facilities to enable them to find the best possible job within the shortest possible time. Job clubs provide a simple, straightforward approach to help clients find jobs. Job club members agree to attend four half days per week. The Jobclub provides use of photocopiers, telephones and typewriters free of charge. Trade magazines and specialist magazines are also available. There may be special types of Jobclubs to help disadvantaged people, i.e. (id est = in other words) former detainees and people nearing release from prison. Executive and Management Job clubs are also available in some areas, which provide support for middle and senior managers. The Work Trials can be regarded as an extended interview. Work Trials offer an employer a period of up to 15 days to observe the jobseeker within the workplace. They also give me job seeker the opportunity to demonstrate their skills and experience to that employer. In addition, they enable the jobseeker to determine their own suitability for that job. Job plan Workshops are to help people who have been out of work for 12 months or more back into work or training. Job plan aims to build participants' resilience to setbacks they may encounter whilst looking for work. Attendance at a Jobplan Workshop gives priority access to ED programmes (education programmes). Job Review Workshops. Aim: to help unemployed people who are unlikely to return to their normal occupation, or who are looking to broaden their jobsearch, make an informed choice of alternative career opportunities. These workshops are particularly suitable for people withprofessional, executive and managerial backgrounds who nave been unemployed for about 13 weeks. Job review workshops are demanding and are particularly suitable for unemployed managers, professional and executive who have been out of work for about 13 weeks; The workshops are facilitated by tutors who can help clients assess what they have to offer in a range of jobs. Participants will have the benefit of a computerized guidance system to help them select the most suitable jobs and men research the most suitable options.

2 года назад

Предмет: Русский язык, автор: Поддубныйqaz

Помогите найти 10 словосочетаний в рассказе Три ветки мимозы

В треугольнике ABC отрезок DE с концами на сторонах AB и BC параллелен к стороне AC. = 4 см², = 5 см², = 7 см. Найти длину AC. А) 9,5 см Б) см В) 12 см Г) 10,5 см Д) 9 см

Ответы