I am used to previous versions of NDK builds which came in zip format. I downloaded the recent r10 version for windows which had a .exe version. The exe version is
r10
For Windows Android Studio 2.3.x(+):
My android-sdk folder was in C:\Program Files\Android\Android Studio\plugins\android-ndk
android-sdk
C:\Program Files\Android\Android Studio\plugins\android-ndk
Be careful: The ndk might not be complete, so make sure everything is up to date.