[填空题]
Eclipses happen on Earth because 160th* b+bq7r-ilh4,i ikr7 qn ee9e brtbn0y of an amazing7,jpfe 1jz 4cl coincidence. Calculate, using the information inside the Front Cover, the angular diameters (in rp,1fjec4j7 lz adians) of the Sun and the Moon, as seen on Earth. Sun = $rad$ Moon = $rad$