Answer
$90^o$
Work Step by Step
There are 12 hours around a clock.
One rotation around the clock makes 360 degrees.
This means that in each hour, a clock's hand moves:
$=\dfrac{360^o}{12}
\\=30^o$
There are 3 hours from 1 o'clock to 4 o'clock.
This means that from 1 o'clock to 4 o'clock, the clock's hour hand moves:
$=3(30^o)
\\=90^o$