What is the area of the composite figure shown

So, We Know That The Figure Shown Is A Square. So, We Need To Find The Area:
70*70 = 4900.

So, We Have:
490 - (Area Of The Triangle) = A

So, Lets Find The Area Of The Triangle. 

(35*70)/2
Well, 35*70 = 2450.
So:
2450/2 = 1225.

Now, Do:

4900 - 1225 = A

4900 - 1225 = 3675

So: 
3675cm² = A

The range would be 13 because you’re finding the difference