Miệng giếng nước là một hình tròn có bán kính 0,7m. Người ta xây thành giếng rộng 0,3m bao quanh miệng giếng. Tính diện tích của thành giếng đó?

Các câu hỏi liên quan

THE FUTURE CONTINUOUS Ex 1. Put the verbs in brackets in the correct tense forms to complete the sentences. 1. I (study) at 8.00 tomorrow. 2. You (wait) for her when her plane arrives tonight? 3. Don’t phone me between 7 and 8. We (have) dinner then. 4. What clothes do you think she (wear) when she arrives? 5. I (send) in my application tomorrow. 6. Linda (arrive) in Ha Noi around March. 7. Next week at this time, you (lie) on the beach. 8. My uncle can’t come to your party tomorrow night because he (work) at night. 9. You (meet) your former teachers at 9 a.m. tomorrowmorning, won’t you? 10. At this time tomorrow evening, I (play) computer games in my bedroom. Ex 2. Rewrite the sentences so that it has similar meaning as the sentence printed before, using the words given. 2. They will build a new school for poor children next month. → A new school A new school will be built for poor children next month. 3. Will the plumber check cracks on the water pipes in two days? → Cracks Will cracks on the water pipes be checked in two days by the plumber 4. They sell these chemicals everywhere in my hometown. → These chemicals These chemicals are sold everywhere in my hometown. 5. They won't show the film on types of future energy sources next Friday. → The film The film on types of future energy sources won’t be shown next Friday. 6. Some people will interview the new president on TV. → The new president the new president will be interviewed on TV. 7. They will destroy the old thermal power plant at the end of this year. → The old thermal the old thermal power plant will be destroyed at the end of this year. 8. They will widen the road to our village next year. the road to our village will be widened next year.