<span>No, 7 is a natural number divisible by 7 and not 14 for example. In fact every odd multiple of 7 (i.e. 7 times 1,3,5,7,...) is divisible by 7 and not 14.</span>
The answer is 45°
By determining the angles of triangle ACB (A=30°, B=45°, C=105° (total of 180°)) and knowing that angle 1 correlates to angle 4 ((1)°=(4)°), we can find angle 1, which is 45°, equal to angle 4.