2.
如图AB⊥CD.垂足为D,ED⊥DF,下列结论正确的有( )
(1)∠ADE=∠CDF(2)∠EDC=∠FDB(3)∠ADE与∠BDF互余(4)∠CDF与∠ADE互补.
(1)∠ADE=∠CDF(2)∠EDC=∠FDB(3)∠ADE与∠BDF互余(4)∠CDF与∠ADE互补.
| A. | 1个 | B. | 2个 | C. | 3个 | D. | 4个 |
1.下列命题中真命题的个数( )
①无理数包括正无理数、零和负无理数;
②过一点有且只有一条直线与已知直线垂直;
③和为180°的两个角互为邻补角;
④正数有两个平方根,且这两个平方根之和等于0.
0 293963 293971 293977 293981 293987 293989 293993 293999 294001 294007 294013 294017 294019 294023 294029 294031 294037 294041 294043 294047 294049 294053 294055 294057 294058 294059 294061 294062 294063 294065 294067 294071 294073 294077 294079 294083 294089 294091 294097 294101 294103 294107 294113 294119 294121 294127 294131 294133 294139 294143 294149 294157 366461
①无理数包括正无理数、零和负无理数;
②过一点有且只有一条直线与已知直线垂直;
③和为180°的两个角互为邻补角;
④正数有两个平方根,且这两个平方根之和等于0.
| A. | 4 | B. | 3 | C. | 2 | D. | 1 |