题目
题型:陇南难度:来源:
3 |
A.120° | B.130° | C.140° | D.150° |
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085844-95576.png)
答案
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085844-42789.png)
如图,作OD⊥AC,垂足为D
∵AB=4
∴OA=2
∵AC=2
3 |
∴AD=
3 |
∵sin∠DOA=
AD |
AO |
| ||
2 |
∴∠DOA=60°
∴∠AOC=120°.
故选A.
核心考点
举一反三
A.74° | B.48° | C.32° | D.16° |
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085841-83598.png)
![]() |
AE |
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085838-60513.png)
下列语句中,正确的个数是( )个.
①相等的圆心角所对的弧相等;
②同圆或等圆中,相等的圆周角所对的弦相等;
③一边上的中线等于这条边一半的三角形是直角三角形;
④等弧所对的圆周角相等;
⑤一条弧所对的圆心角等于它所对的圆周角的一半.