You Do Need power plug adapter while traveling from Myanmar (Burma) to Cook Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Cook Islands is I and in Myanmar (Burma) are A, C, D, G and I. This is how they look like.

Myanmar (Burma)

In Myanmar (Burma), outlets of type A, C, D, G and I are in use.

Type A

Type C

Type D

Type G

Type I

Cook Islands

In Cook Islands, outlets of type I are in use.

Type I