Find the angle between the hour hand and minute hand of a clock when it is 9:20.

Guest Jun 16, 2020

#1**+2 **

At 9:40, the minute hand is at 4 and the hour hand is between 9 and 10.

There is \(30 ^\circ*5=150^\circ\)between the minute hand and 9 o'clock.

The hour hand is \(\frac{20}{60}*30^\circ=10^\circ\) past 9 o'clock.

So our answer is \(150^\circ+10^\circ=160^\circ\)

thelizzybeth Jun 16, 2020

#2**+1 **

Hour hand moves .5 degree per minute and starts at 270 degrees at nine o'clock

So hour hand is at. 270 + (20*.5)= 280^{o}

^{ Minute hand is at 120 degrees at 20 after}

280-120=160^{o } between the hands....

ElectricPavlov Jun 16, 2020

#3**+1 **

**Find the angle between the hour hand and minute hand of a clock when it is 9:20.**

**\(\begin{array}{rcll} \Delta\alpha^{\circ} &=& 330 \times t^h \pmod{360^{\circ}} \quad | \quad \mathbf{t^h=9+\dfrac{20}{60} = \dfrac{28}{3}\ h } \\ &=& 330 \times \dfrac{28}{3} \pmod{360^{\circ}} \\ &=& 3080^{\circ} \pmod{360^{\circ}} \\ &=& \mathbf{200^{\circ}} \qquad (\text{greater angle)} \\ &=& \mathbf{360^\circ-200^{\circ}=160^\circ} \qquad (\text{smaller angle)} \\ \end{array} \)**

heureka Jun 17, 2020