Related angles: angles of quadrilateral inscribed in circle

[luissi]

sorry, I didn't really know what to call this post, but anyways.

How are angless BAD and BCD related?


PS: the illustration I made in paint to resemble the one in my book.
Please help me, I'm really lost

 

[skeeter]

since they are both angles inscribed in a circle that intercept the same arc BD. they are equal in measure.

go to this link to learn more about angles inscribed in circles.

 

[luissi]

thanks so much!

 

[soroban]

Re: Related angles

Hello, luissi!

How are angles \(\displaystyle BAD\) and \(\displaystyle BCD\) related?

An inscribed angle ismeasured by one-half its interecepted arc.

Draw chords \(\displaystyle AD\) and \(\displaystyle BC.\)

\(\displaystyle \angle BAD\) and \(\displaystyle \angle BCD\) are inscribed angles.
. . They are both measured by: \(\displaystyle \frac{1}{2}(\text{arc} BD)\)

Therefore: \(\displaystyle \:\angle BAD \:=\:\angle BCD\)

 

[luissi]

thank you!