Question 152270
2*THE ORIGINAL SQUARE PERIMETER IS THE PERIMETER OF THE 10 cm & 6 cm EXTENDED SIDES OF THE SQUARE TO FORM A RECTANGLE.  
2*4X=2(X+10)+2(X+6)
8X=2X+20+2X+12
8X-4X=32
4X=32
X=32/4
X=8 FOR THE ORIGINAL SIDES OF THE SQUARE (AB & AD)
PROOF:
2*4*8=2(8+10)+2(8+6)
64=2*18+2*14
64=36+28
64=64