Question 139573
How do I find the Measure of arc BC?
<pre><font size = 5 color = "indigo"><b>
Arc BC is is subtended by the inscribed angle BAC.

Theorem to use:
<i>The measure of an arc subtended by an inscribed angle is twice
the measure of the inscribed angle.</i> 

Since the sum of the measures of the angles of triangle ABC is
180°, 

m(angle A) + m(angle B) + m(angle C) = 180°

              m(angle A) + 68° + 62° = 180°

                   m(angle A) + 130° = 180°
                               -130°  -130°
                 ---------------------------
                          m(angle A) =  50°

So by the theorem, the measure of arc BC is twice 50° or 100°.

Edwin</pre>