## Thinking Mathematically (6th Edition)

$90^o$
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: $=3(30^o) \\=90^o$