Understanding orientation and scaling

My game has 2 different interfaces for landscape and portrait mode.
I set the canvas as 1136 x 640
Fit Height

Then set the orientation to Auto

When I build and ran the game landscape mode the game display correctly.
But on portrait mode everything is scale up.

I ran the game on Galaxy S5, landscape mode window size is giving as (1136.00, 640.00)
portrait mode window size is coming as (360.00, 640.00) , shouldn’t it be (640,1136) ?

Can someone explain what is going on?
The game is designed to 1136 x 640 scale. so how do i find the correct scale i have to apply ?

Was you able to manage it? Can you please share how?