let's set up an equation:
x-4=9
solve normally:
x=13
Convert mixed number to improper fraction:

Answer:
40 square units
Step-by-step explanation:
First of all, lets say that square has side
, so, the area unit is 
the diagonal's square is 
CALCULATION OF TRIANGLES'S AREA (there are 4 triangles)

CALCULATION OF MAIN SQUARE AREA

TOTAL AREA

Answer:
604.58
Step-by-step explanation:
because hegarty says its 604.58
(10 1/2)/(3/8)
= (21/2)/(3/8) Convert to improper
= (21/2)*(8/3) Multiply by reciprocal of second
=(7/1)*(4/1) Cross reduce
=28 Multiply