Question

Arc Length: Suppose Figure 1 is an exaggerated diagram of a plane flying above Earth. When the plane is 4.55 miles above point B, the pilot finds angle A to be 90.8 degrees. Assuming that the radius of the Earth is 3,960 miles, what is the distance from point A to point B along the circumference of the Earth? (Hint: Find angle C first then use the formula for arc length)