Предмет: Геометрия, автор: abcdefg01

СРОЧНО НУЖНО РЕШИТЬ!!!!!!
ДАЮ 40 БАЛЛОВ!!!!!!!!

Приложения:

Ответы

Автор ответа: Andr1806
0

Ответ:

АС = 22 ед.

Объяснение:

По рисунку ВМ - медиана треугольника АВС, проведенная к стороне АС.

Формула для нахождения медианы:

Мас = (1/2)·√(2·АВ²+2·ВС²-АС²).  

Дано: Мас = 7 ед. АВ = 12 ед. и ВС = 14 ед.  =>

7 = (1/2)·√(288+392-АС²).

Возведем обе части равенства в квадрат:

49 = (1/4)·(658 - АС²)  => АС² = 658 - 49·4 = 484.

АС = √484 = 22 ед.

Предыдущий вопрос
Следующий вопрос
Похожие вопросы
Предмет: Английский язык, автор: Аноним
Ркбята я вас умоляю мне очень надо пожалуйсто!!!!!очень очень
1 год назад
Предмет: Русский язык, автор: trixi1989vv
Укажите падеж. Хозяйка, над лужайкой, над цветком, медком. Запишите слова в три столбика. Меч, яйцо, вода, рот, печь, дым, щель, нога, ферма, мебель, дочь, вишня.
1 год назад
Предмет: Русский язык, автор: 83urok
Мини сочинение на тему Доброта
1 год назад
Предмет: Математика, автор: marina6939
сумма сторон прямоугольника с тремя равными сторонами 9м. Чему равна его сторона?
7 лет назад
Предмет: Английский язык, автор: H1kk4Kun
Переведите плиз текст




Alexei is going to leave school in a year, but he realizes that he must

start thinking about further education right now, because it is

essential

to read for exams well beforehand. So he asks his brother to

tell him

about his college and advise.

 

Alexei: Vlad,I want to ask you about college life. Is it different from

school life?

Vlad: Well, it depends on what you are interested in. We, too, in college have lessons, and marks; teachers give us homework,

and there are examinations and tests.

 

 

Alexei: Well,I see. But, then, is there any difference between a

 

school and a college?

 

 

Vlad: Why, of course. First, at college we

have special

subjects in

our curriculum. For example, if one

is going to be a teacher,

he or she will take pedagogy, psychology, and methods of

teaching. If one wants to become an economist,

he or she

will study economics, accounting, taxation and a lot of other

things. It’s really very interesting. Second, if you

work regu­

larly, attend all the lectures and seminars, and get good marks, you will be given a scholarship. If you are at the top of the group, and have excellent marks, the scholarship will be higher.

Alexei: It sounds very nice, I must say. Now, please, describe your usual day at college.

Vlad: Well, our day starts in the assembly hall, where we all gather

together and the head teacher

calls the register. Then the

classes begin. We have several

lectures and seminars every

day, and work in workshops. Students also can stay at col­

lege after classes to do research.

 

Alexei: How are students assessed?

Vlad: We have exams and credit tests twice a year. But of course, it is important how you work during the year.

Alexei: What is the difference between an exam and a credit test?Vlad: Well, you get marks for an exam, and when you take a credit

test, you’ll get a “pass”. Exams are usually taken at the end

192

of the course of a subject. For example, if you take chemistry for a year and a half, you will have credit tests in chemistry at the end of two terms, and at the end of the third term you will take an exam.

Alexei: Is an exam more difficult, than a credit test.

Vlad: Not really. In fact, you have more time to read for an exam: you are given from two to five days to get ready, and you are

not given a lot of

time to get ready for a credit

test.

In

general, it depends on the subject.

 

 

Alexei: Well,I see. Now,

what about holidays? They are

not

the

same as at school, are they?

Vlad: We have holidays only two times a year: two weeks in Febru­ ary and two and a half months in summer.

Alexei: Vlad, what are you going to do after you graduate?

Vlad: There is a good opportunity for those who get only excellent

marks while they study. When we graduate, we can enter a university without taking entrance exams and continue our education there. That’s why I study hard and try to work

regularly, and not by fits and starts. And

hard work

gives

good results, as I am at the top of the group now.

 

 

 

Alexei: The

prospect is very nice. I wish you good luck, then. Do

you advise me to enter this college, too?

 

 

 

Vlad: You know, it’s up to you to decide. But I

like my studies

there, and I think I have made the right choice. Besides,

I’ve

got many friends in the

college, and friendship is the

best

thing in the world!
7 лет назад