# 义务教育课程标准实验教科书 - PowerPoint PPT Presentation

1 / 8

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

#### Presentation Transcript

24.1.3 垂直与弦的直径

(弧所对的弦的长)为37.4m,拱高(弧的中点到弦的距离)为7.2m，你

?

（1）圆是轴对称图形吗？如果是，它的对称轴是什么？

（2）你能发现图中有那些相等的线段和弧？为什么？

C

（1）是轴对称图形．直径CD所在的直线是它的对称轴

·

（2） 线段： AE=BE

O

E

B

A

D

AE＝BE， ，

C

·

O

E

B

A

D

C

D

B

A

R

O

AB=37.4，CD=7.2，

OD=OC－CD=R－7.2

1．如图，在⊙O中，弦AB的长为8cm，圆心O到AB的距离为3cm，求⊙O的半径．

·

E

A

B

O

2．如图，在⊙O中，AB、AC为互相垂直且相等的两条弦，OD⊥AB于D，OE⊥AC于E，求证四边形ABOE是正方形．

·

C