Предмет: Геометрия, автор: evtusenkomatvej6

Геометрия 9 класс помогите пожалуйста ​

Приложения:

Ответы

Автор ответа: akunyaastana
0

Ответ:

\tan( \alpha ) = \frac{ \sin( \alpha ) }{ \cos( \alpha ) } \\ \sin( \alpha ) = \tan( \alpha ) \times \cos( \alpha ) = \frac{15}{20} \times 20 = 15

Автор ответа: table123
0

Ответ: sina=3/5

Объяснение:  

формула  1+tg^2 a=1/cos^2 a,  1/cos^2 a=1+(3/4)^2,  1/cos^2 a=1+9/16=25/16,

1/cosa=5/4,  cosa=4/5,  sin^2 a=1-cos^2 a=1-16/25=9/25,  sina=3/5

Предыдущий вопрос
Следующий вопрос
Интересные вопросы
Предмет: Українська мова, автор: Lee7Felix
пж срочно потрібно ​
5 лет назад
Предмет: Геометрия, автор: zajcenkoalina90
Радіус кола , вписаного в прямокутний трикутник дорівнює 4 см.Очисліть периметр цого трикутника,якщо його гіпотенуза дорівнює 26 см
5 лет назад
Предмет: Английский язык, автор: Griegg
помогите с тестом пожалуйста
1. Find phrases where the is pronounced as [€i]
A) the end B) the sun C) the other way D) the cinema E) the worlds

2. Replace underlined word with its opposite. She is always obedient.
A) misobedient B) disobedient C) overobedient D) inobedient E) notobodient

3. The correct proverb. Last year I worked very hard at my Math and English. I spent all my time reading and preparing for my entrance exams. My motto was: . . .
A) No pain, no gains B) A bird in hand is worth two in the bush C) Speech is silver but silence is gold D) Better short of pence than short of sense E) Look before you leap

4. A motorbike is . . . a scooter.
A) the most powerful B) most powerful C) as powerful D) powerful E) more powerful than

5. I love watching fireworks, but the noise sometimes makes . . . nervous.
A) our B) me C) their D) his E) my

6. . . . ‘s the doctor. . . . daughter is in this class.
A) she/her B) we/our C) he/himself D) they/their E) we/their F) it/its E) she/we

7. I am afraid the box is . . . to carry.
A) more heavy B) the heaviest C) most heavy D) too heavy E) heavier

8. Match the numbers with its writing: 28.5.
A) twenty eight and five B) twenty eighth point five C) twenty eight point fifth D) twenty eight point five

9. She’s just moved from her flat . . . 38 Azalea Drive.
A) to B) on C) for D) in E) at

10. . I never argue . . . my husband . . . money.
A) with/about B) in/at C) of/for D) for/on E) to/for

11. Find the odd word from the list below:
A) friends B) braces C) tongs D) handcuffs E) leggings

12. Don’t laugh . . . my work. I am doing my best.
A) with B) at C) of D) for E) to

13. I read the paper . . . the taxi on the way.
A) in B) on C) at D) for E) to

14. Crew is often used for the staff of . . .
A) an ambulance B) a plane C) a school D) an engineers E) a hospital

15. 7/9
A) seven and ninth B) seven ninth C) seven and nine D) seven nine E) seventh nine

16. . Look at that . . . window.
A) broke B) is broken C) broken D) to break E) has broken

17. She gave me a ... box.
A) small, square, metal, jewelry B) jewelry, metal, small, square C) metal, small, square, jewelry D) small, metal, jewelry, square, E) square, small, metal, jewelry

18. Choose sentences with correct question tags.
A) We’ve met before, haven’t we? B) You are going out with him, don’t you?
C) They didn’t have enough evidence, did they? D) You won’t tell any lies, don’t you?
E) You didn’t know he was a criminal, did you? F) The police have arrested someone, hasn’t he?

19. Choose the odd word from the list below.
A) childhood B) manhood C) neighbourhood D) priesthood E) brotherhood

20. Find the works of the great English writer William Shakespeare.
A) Alice in Wonderland B) King Lear C) Romeo and Juliet D) Pride and Prejudice E) Merchant of Venice F) Treasure Island G) Oliver Twist H) Brown Wolf

21. .If he … a car accident yesterday, he … in hospital now.
A) hadn’t had/wouldn’t B) hadn’t had/wouldn’t be C) wouldn’t had/wouldn’t be D) hadn’t/wouldn’t be E) hadn’t be/wouldn’t had

22. .We ask them when …
A) will they coming back B) d they come back C) they are coming back D) did they come back E) are they come back

23. Match the abbreviation with its meaning: FBI.
A)Full board of interests B) Free Business inquiry C) Interest rate D) Federal Board of Investors E) Federal Bureau of Investigation

24. Find the incorrect phrase.
A) at the same time B) at one time C) at that time D) for a long time E) in the long time

25. Choose an appropriate reported speech sentence “I have found my keys!”
A) She announced that she had found her keys B) She announced that she found her keys
C) She announced she has found her keys D) She announced that she found her keys
E) She announced she have found her keys.
5 лет назад
Предмет: География, автор: Akbotta
Известно, что температура на поверхности Мирового океана разная. Как и почему она меняется? Может ли она быть отрицательной?
9 лет назад
Предмет: Математика, автор: aikowka1
помагите плиззз 9 задачу
9 лет назад