Exterior angles

Suppose,

The number of sides=x

Sum of exterior angle of regular polygon is $360^\circ$

If The number of sides=x

then each exterior angle= $(\dfrac{360}{x})^\circ$

So,according to the condition now we get,

$\dfrac{360}{x}=5$

$or,360=5x$

$\large\boxed{or,x=72}$

So,

the number of sides of a regular polygon whose exterior angles are $5^\circ$ each is $72$ .