Decades: 1190s 1200s 1210s 1220s 1230s - 1240s - 1250s 1260s 1270s 1280s 1290s
Years: 1242 1243 1244 1245 1246 - 1247 - 1248 1249 1250 1251 1252
Births
Deaths
... left side is now a perfect square; it is the square of (x + b/(2a)). The right side can be written as a single fraction; the common denominator is 4a2. W ...