摘要： Given the area of △ABC is S1 ,and the length of its three sides are,10 respectively. And the perimeter of △A′B′C′ is 18 , its area is S2. Then the relationship between S1 and S2 is S1 S2 . ( fill in the blank with ">"," = " or "<") (英汉词典:area面积,length长度,perimeter周长)
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Given in the△ABC，a，b，c are three sides of the triangle，and
=
+
，then∠A is（ ）
（英汉词典acute angle：锐角；obtuse angle：钝角）
| 3 |
| a |
| 2 |
| b |
| 1 |
| c |
（英汉词典acute angle：锐角；obtuse angle：钝角）
| A、acute angle |
| B、right angle |
| C、obtues angle |
| D、acute angle or obtues angle |
If we have
＜0，a-b＜0 and a+b＞0，then the points in real number axis，given by a and b，can be represented as （ ）
（英汉词典point：点；real number axis：实数轴；represent：表示）
| a |
| b |
（英汉词典point：点；real number axis：实数轴；represent：表示）
A、 |
B、 |
C、 |
D、 |
Given two non-zero real numbers a and b，satisfy |2a-4|+|b+2|+
+4=2a，then the value of a+b is（ ）
| (a-3)b2 |
| A、-1 | B、0 | C、1 | D、2 |