Properties Of Circles

1. tan. $\perp$ rad.
2. rt. $\angle$ in semicircle
3. $\angle$s in same seg.
4. $\angle$ at centre = 2 $\angle$ at circ.
5. $\angle$s in opp. seg. ($a+c=b+d=180^\circ$)
6. tan. from ext. pt.