Hmm, first of all, the angular size of the moon is around [tex] 0,5^{o} [/tex] . When we measure sizes of objects in the sky, we cannot determine how far each of them lies and we cannot acoount for that; so for example, the sun and the moon have roughly the same size on the sky, despite the sun being much bigger in reality. This "sky-size" is measure with how big an angle the spherical object takes up in the sky (and specifically how big an angle a diameter of that object takes up). A whole circle around the night sky takes up 360 degrees, so 720 moons could fit in this circle (approximately). We see that a degree is a big unit of measurement, so we have smaller ones. Degrees have a subdivision, arcminutes. One arcminute is 1/60 of a degree. Thus 1 degree has 60 arcminutes in it. Hence, half a degree contains 30 arcminutes. Thus, the moon has roughly an angular size of 30 arcminutes.
