Ben and Sadie are doing a sponsored walk around a circuit.
Ben takes 25 minutes to do one circuit and Sadie takes 45 minutes.
They start together at 9:30 am.
When will they next cross the start line together?

25=52 and 45 = 5•32  

The least common multiple has to be 52•32 = 9 times 25 = 225 minutes, which is 3 hours + 45 minutes.

by definition, an arc subtended by a central angle of some given measure has the same measure. so .

if x = 1, then the answer is 3.5