Question

Question 5 (e)

Find the number of right angles turned through by the hour hand of a clock when it goes from:
12 to 9

Answer 1

A complete revolution of the hour hand covers 12 hours or four right angles i.e ${360}^{\circ }$.Which means 1 hour = ${30}^{\circ }$.
When the hour hand goes from 12 to 9, the time difference = 9 hours i.e three-fourth of 12 hours.
$\Rightarrow$ $\frac{3}{4}$ of ${360}^{\circ }$
$\Rightarrow$ ${270}^{\circ }$
= Three right angles.