Solid angle at an average angular diameter of 0.5334 degrees or 9.310 radians. The Moon is seen from Earth at an average angular diameter of 9.22 radians. We can substitute these into the equation given above for the solid angle subtended by a cone with apex angle : The resulting value for the Sun is 6.807 steradians. The resulting value for the Moon is 6.67 steradians. In terms of the total celestial sphere, the Sun and the Moon subtend "fractional areas" of 0.000542% (Sun) and 0.000531% (Moon). On average, the Sun is larger in the sky than the Moon even though it
Degree (angle) this system. In most mathematical work beyond practical geometry, angles are typically measured in radians rather than degrees. This is for a variety of reasons; for example, the trigonometric functions have simpler and more "natural" properties when their arguments are expressed in radians. These considerations outweigh the convenient divisibility of the number 360. One complete turn (360°) is equal to 2"" radians, so 180° is equal to radians, or equivalently, the degree is a mathematical constant: 1° = . The turn (or revolution, full circle, full rotation, cycle) is used in technology and science. One turn is equal to 360°.