Exercise 62 Page 803

The measure of an angle formed by two lines that intersect outside a circle is half the difference of the measures of the intercepted arcs. The angle formed by the intersection of the lines outside the circle measures a^(∘). One of the intercepted arc measures 218^(∘). The other intercepted arc measures 142^(∘).

With this information we can write an equation and solve it to find the value of a. a=1/2(218- 142) ⇔ a= 38