Help with scale drawing and areas

[Secret.7]

Hi
I would be very grateful if someone could help me with the below problem, please:

I have completed a scale drawing of my living room, the scale is 1:30 cm. I have worked out that the area is 240.05 cmsq scaled. I now need to convert this back to the full size and I'm not sure how to do it. Do I multiply it by 900 to get the full size in cm sq. and then decide by 10000 to get the metre sq? Or am I on the wrong track altogether.

thank you in advance

 

[pappus]

...
Do I multiply it by 900 to get the full size in cm sq. and then devide by 10000 to get the metre sq? Or am I on the wrong track altogether.

thank you in advance

Correct!

 

[Secret.7]

Thank you very much for the reply