Since the area of a circular sector with radius "r" and angle "u" (in radians) is "r""u"/2, it will be equal to "u" when "r" = . In the diagram, such a circle is tangent to the hyperbola "xy" = 1 at (1,1). The yellow sector depicts an area and angle magnitude. Similarly, the yellow and red sectors together depict an area and hyperbolic angle magnitude.