问题 选择题

三角形内到三条边的距离相等的点是(   )

A.三角形的三条角平分线的交点

B.三角形的三条高的交点

C.三角形的三条中线的交点

D.三角形的三边的垂直平分线的交点

答案

答案:A

分析:题目要求到三边距离相等,可两两分别思考,根据角平分线上的点到角两边的距离相等可得答案.

解答:解:中线交点即三角形的重心,三角形重心到一个顶点的距离等于它到对边中点距离的2倍,C错误;

高的交点是三角形的垂心,到三边的距离不相等,B错误;

线段垂直平分线上的点和这条线段两个端点的距离相等,D错误;

∵角平分线上的点到角两边的距离相等,

∴要到三角形三条边距离相等的点,只能是三条角平分线的交点,A正确.

故选A.

点评:本题考查了角平分线的性质;熟练掌握三角形中角平分线,重心,垂心,垂直平分线的性质,是解答本题的关键.

多项选择题 X型题
完形填空

完形填空(共20小题;每小题1.5分,满分30分)

阅读下面短文,掌握其大意,然后从36-55各题所给的四个选项(A、B、C和D)中,选出最佳选项,并在答题卡上将该项涂黑。

Many people go to school for  36 . They learn languages, history, geography, physics, chemistry and mathematics.  37  go to school to learn a skill  38 they can make a living. School education is very important and useful. Yet no one can learn  39 from school. A teacher, no matter how much he  40 , can not teach his students everything they  41  to know. The teacher’s job is to show his students  42  to learn. He teaches  43 how to read and how to think. So much more is to be learned  44  school by the students themselves.

It is always more  45  to study by oneself than to remember some facts or formulas (公式). It is quite  46  to learn a certain fact in history  47  a formula in mathematics. But it is very difficult to  48  a formula in working out a maths problem. Great  49  such as Einstein, Newton and Galileo didn’t get everything from school. But they were  50  successful. They knew  51  to study, they read books that  52 not taught at school. They worked hard all their lives  53  not a single moment. They  54  ask many questions as they read and they did thousands of experiments.

Above all, they knew how to use their  55  .  

36. A. education  B. educating      C. study     D. learning

37. A. Other      B. Others    C. The other      D. Another

38. A. such that   B. so as to         C. so that    D. in order

39. A. nothing    B. something      C. anything        D. everything

40. A. understands   B. will know   C. knows     D. knew

41. A. eager        B. want      C. ask        D. wanted

42. A. how         B. what      C. when     D. where

43. A. the teacher  B. them     C. student    D. the student

44. A. at      B. inside     C. outside    D. out

45. A. possible    B. important       C. impossible      D. unimportant

46. A. easy         B. uneasy          C. difficult        D. hard

47. A. but                 B. and       C. or         D. other

48. A. learn       B. use        C. study     D. work

49. A. scientists  B. teachers         C. students         D. people

50. A. either       B. both       C. all         D. neither

51. A. what        B. which           C. this        D. why

52. A. is      B. were      C. will be          D. have been

53. A. waste       B. wasted          C. wasting         D. to waste

54. A. could       B. should    C. might     D. would

55. A. cleverness        B. thoughts        C. hearts     D. brains