Question

10.1.3The hour hand of a clock moves from 5 to 9 o'clock. Through how many degrees does it move?

Answer 1

Step 1: Lets calculate angle on each hour hand

since the wall clock takes the shape of a cirle

Therefore,

The total angles in a walk clock is 360°

Angle on each hour hand is

There are 12 hour hands on the clock ,

Therefore,

`\begin{gathered} \text{Angle on each hour hand is =}\frac{360^0}{hands\text{ on the clock}}^{} \\ \text{Angle on each hour hand =}(360^0)/(12)=30^0 \end{gathered}`

Since the hour hand moved from 5 o'clock to 9 o'clock

It has moved a distance of (9 - 5)= 4 hands on the clock

If each hand on the clock=30°

Therefore,

The angle in degrees moved through 4 hour hands on the clock will be calculated as,

`\begin{gathered} \text{Angle moved = angle on each hand}* no\text{ of hands moved} \\ \text{Angle moved=30}^0*4=120^0 \end{gathered}`

The hour hand of the clock moved from 5 o'clock to 9 o'clock through an angle of 120°