Cho tam giác nhon các đường cao AD BE cắt nhau tại H A) c/m 🔺️AEB đồng dạng với 🔺️AFC . Từ đó suy ra AF.AB=AE.AC B)c/m AEF= ABC c) cho AE=3cm,AB= . Cminh SABC=4SAEF

Một hình chóp tứ giác đều( đáy là hình vuông). Thể tích của hình chóp là 60cm^3, chiều cao là 5cm. Tính độ dài cạnh đáy của hình chóp

32. You may use this room for the meeting place 33. We may organize a seminar this morning 34. People should plant potatoes in spring → 35. Someone ought to paint that fence 36. Someone had to fix our car before we left for Chicago -> 37. People cannot control the weather 38. John is cleaning the bakery at present 39. Peter will do this exercise tonight. 40. People have cooked the vegetables for too long. →.. 41. Mary has written a composition since 8 o'clock. 42. Careless driving causes many accidents. 43. They don't invite me to parties. .. 44. Look! Someone is feeding the seals. ... 45. You should open the wine about three hours 46. The bus will take the workers home. 47. They have to sell their house to pay their debt ... 48. Nobody has invited her to the party. 49. Mary teaches grammar and writing. 50. Lan bought her brother some comic books.