15pc是多少ly？
15pc = 48.9235ly
是48.9235ly，所以說成49ly也沒問題——四捨五入的誤差在0.5%以內。
反過來，15ly是多少pc？
15ly = 4.599pc
計算公式: ly = pc × 3.261564
該數值前後的 pc → ly
6 pc19.5694ly
7 pc22.8309ly
8 pc26.0925ly
9 pc29.3541ly
10 pc32.6156ly
11 pc35.8772ly
12 pc39.1388ly
13 pc42.4003ly
14 pc45.6619ly
15 pc48.9235ly
16 pc52.185ly
17 pc55.4466ly
18 pc58.7081ly
19 pc61.9697ly
20 pc65.2313ly
21 pc68.4928ly
22 pc71.7544ly
23 pc75.016ly
24 pc78.2775ly
25 pc81.5391ly