Perpendicular lines meet at right angles (90&deg;).<br><br>
&bull; AOB is perpendicular to COD, so they meet at 90&deg;<br>
&bull; At point O, angle AOC = 90&deg; and angle COB = 90&deg;<br>
&bull; These are the two right angles formed by the perpendicular lines<br><br>
Final Answer: AOC, COB