The radius of circle is 15 miles. what is the area of a sector bounded by a 70o arc?

If the area of the sector is bounded by a 70° arc then that is also the measure of the central angle in question.  The formula for the area of a sector is .  We now have our angle beta and we were given the radius, so filling in accordingly, we have which simplifies to .  If you have to leave your answer in terms of pi, then you're done.  If you have to multiply in the value for pi, you would have 137.44 miles squared.