1. ## circle proof

trying to use angles on the same arc theorem

2. ## Re: circle proof

Originally Posted by markosheehan

trying to use angles on the same arc theorem
\begin{align*}|\angle CDL|&=0.5(|arc(CL)|-|arc(AB)|\\|\angle CAL|&=0.5|arc CL|\\|\angle ACB|&=0.5|arc AB| \end{align*}

3. ## Re: circle proof

im confused. how does the angle CDL =.5 the size of the arc CL - size of arc AB

4. ## Re: circle proof

Originally Posted by markosheehan
im confused. how does the angle CDL =.5 the size of the arc CL - size of arc AB
$|\angle CDL|=0.5(|arc(CL)|-|arc(AB)|)$
The point $D$ is exterior to the circle. The segments $\overline{DC}~\&~\overline{DL}$ both intersect the circle "cutting off" two arcs.
It is a theorem that $|\angle CDL|$ is one-half the difference in the measures of the major & minor arcs.