题目
题型:青神县一模难度:来源:
A.80° | B.40° | C.60° | D.45° |
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085201-23746.png)
答案
∴∠ACB=
1 |
2 |
1 |
2 |
故选B.
核心考点
举一反三
CD |
AB |
A.sin∠AED | B.cos∠AED | C.tan∠AED | D.以上都不对 |
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085158-81277.png)
“已知:如图,点A、B、C是半圆上三点,CD⊥AB于D,AD=9cm,CD=6cm,BD=4cm.请你补充一个结论并证明.”
小红看完后高兴的笑了,“哈哈AB是半圆的直径!”
你认为小红的说法正确吗?若正确,请帮小红完成证明;若不正确,请你补充一个结论并证明.
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085154-62748.png)
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085150-57708.png)
(1)求证:△ADE∽△ACD;
(2)求AB的长.
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085146-68248.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085143-75589.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191105/20191105085143-78404.png)