1. ## proving isoceles tirangle

i need help with proving the 1st part.thx

2. Originally Posted by helloying
i need help with proving the 1st part.thx
HI

Since BC is parallel to AD , it is clear that $\angle CBD=\angle BDA$ and

$\angle BCA=\angle CAD$

Now use the properties of circles , where angles in the same segment are equal , so

$\angle BCA=\angle BDA$ and $\angle CBD=\angle CAD$ .

and you should be able to make your deduction now .