The English does not make sense. How about: "This room is twice as big as mine" or "The size of this room is twice my room's size".
The area of this room is twice that of my room!
Bad English, frustrating to be marked wrong in my native language
This room is double my room!
This room is twice the size of my room!
"The area of this room is twice my room!"
The audio seems to be wrong....