To find the length of major arc BE, you must know two things: the measure of the central angle that intersects the circle at its endpoints and the radius of the circle. Because ABCD is a rectangle, and rectangles only have right angles, figuring out the measure of the central angle is simple. is 90º, so the measure of the central angle is 360º – 90º = 270º.

 

    Finding the radius of the circle is a little tougher. From the diagram, you can see that it is equal to the height of the rectangle. To find the height of the rectangle, you can use the fact that the area of the rectangle is 18, and the length is 6. Since A = bh, and you know the values of both a and b,

    With a radius of 3, we can use the arc length formula to find the length of major arc BE.