I installed NDK using Android Studio (SDK Manager). Where is the default directory of NDK for Mac? How do I find the path to it?
My understanding is that now the NDK bundle is being offered via the SDK Manager within Android Studio, it will install into the Android SDK directory as per the other components (platforms, build tools, support repositories, etc.) in the SDK Manager.
You can check the location of the SDK directory itself via Android Studio -> Preferences... -> Appearance & Behavior -> System Settings -> Android SDK -> Android SDK Location field near the top of the panel.
I've customised mine (it's editable) so I'm afraid I don't know what the default is, but if you check the contents of the directory listed in that field then the NDK should be installed into a subdirectory called ndk-bundle.