Предмет: Геометрия, автор: Bobik23598

Нам необходимо склеить из бумаги цилиндр высотой 20 см и с диаметром основания 10 см.

Какую площадь (в см^2) займёт развёртка для нашей бумажной модели, если не считать клапаны для склейки?

Площадь круга считаем по формуле S=пr^2, где r — радиус круга, а п=3,14


ГАЗ52: Чтобы найти площадь (в см^2) развёртки необходимо к площади боковой поверхности прибавить площадь основания. Площадь боковой 2πr•h.
2•3,14•5•20=628
S осн=πr²=3,14•25=78,5
Оснований два 78,5•2
S общ=628+78,5•2

Ответы

Автор ответа: ludmilaksenija2005
2

Объяснение:

h=20 cм

d=10 см

π=3,14

r=d/2=10/2=5 см

Sполн=2Sосн+Sбок

Sосн=πr²=3,14•5²=78,5 см²

Sбок=2πr•h=2•3,14•5•20=628 cм²

Sполн=2•78,5+628=785 см²

ответ: 785 см²

Похожие вопросы
Предмет: Математика, автор: gospodinNET
Предмет: Алгебра, автор: Highto
Предмет: Английский язык, автор: Yatoxxxxxx
1. Put the sentences into a negative (-) or an interrogative (?) form. 1. All the family go for a walk in the evenings. (?) 2. Jane plays the violin brilliantly. (-) 3. They are working on their project at the moment. (?) 4. The Jacksons stayed in a luxurious hotel. (-) 5. He had a little house in a village. (?)
2. . Choose the correct point. 1. ….. Tom and Bob good football players? a) am b) is c) are 2. They ……………….a new car. a) has got b) has c) have 3. …………… money do you have? a) How much b) How many c) How 4. My sister …………… two foreign languages. a) is speaking b) speaks c) speak 5. The seminar starts …. 10 o’clock. a) in b) at c) on 6. Go …… the blackboard, please! a) to b) at c) in 7. Diana …………… to the party tomorrow. a) comes b) is coming c) came 8. Mary ……….. tennis two days ago. a) played b) plays c) is playing 9. I’m glad he looks …………. today. a) happiest b) happyer c) happier 10. My flat ………. very modern. a) are b) is c) – 11. John ……….. his granny three times a week. a) visits b) is visiting c) visit 12. We ………… hard this week because of the exam. a) study b) are studying c) studies 13. My favourite side dish is mashed …………. . a) potato b) potatos c) potatoes 14. Her grandparents live in the country and have a lot of ………….. . a) sheep b) sheeps c) sheepes 15. ………… bag is it? Maria’s? a) who b) who’s c) whose 16. There is …………. to do here. I lie on the bed all day. a) something b) anything c) nothing 17. Ben doesn’t like very sweet tea. He usually puts ………… sugar in it. a) little b) few c) much 18. Would you like …………… to read on the train? a) something b) anything c) nothing 19. I wanted to talk to Sarah and sat down …………. her. a) far from b) next to c) below 20. It is my ………… time here. a) twelve b) twelveth c) twelfth 21. She is ………. player in the team. a) the strongest b) a stronger c) strong 22. She is as …………. in Maths as her sister. a) better b) best c) good 23. He can’t talk to you now. He ………….. a shower. a) is takeing b) is taking c) taking 24. I ………… you now even more than before. a) am loving b) love c) loving 25. George arrived in Moscow ……… . a) two days ago b) in two days c) today 26. We ……….. a dictation yesterday. a) didn’t wrote b) didn’t write c) don’t write 27. There ………...... a lot of milk in the fridge. a) are b) – c) is 28. There ………. six desks in the classroom. a) are b) some c) is 29. My brother ………… near our house. a) don’t live b) doesn’t lives c) doesn’t live 30. I’d like to ………… karate. a) go b) do c) play ,