3. The length of the minute hand of a clock is 14 cm. Find the area swept by the minute hand in 5 minutes.

Answers (1)
D Devendra Khairwa

The minute hand rotates 360o in one hour.

We need to find rotation in 5 min.  :-        

                                                              =\ \frac{360^{\circ}}{60}\times 5\ =\ 30^{\circ}

The area of sector is given by :    

                                                        \\Area\ =\ \frac{\Theta}{360^{\circ}}\times \pi r^2\\\\Area=\ \frac{30}{360^{\circ}}\times \pi \times 14^2\\\\Area=\ \frac{154}{3}\ cm^2                                                            

Hence the area swept by minute hand in 5 minutes is \frac{154}{3}\ cm^2.