Answer:
Step-by-step explanation:
If you have a square of side [tex]l[/tex], its diagonal would be [tex]l\sqrt{2}[/tex], and its area [tex]l^2[/tex]
If the big square has a area of 900, this implies that its side is [tex]\sqrt{900}[/tex], so the two diagonal of squares 2 and 4 added together would be [tex]\sqrt{900}[/tex], therefore one diagonal wold be [tex]\frac{\sqrt{900}}{2}[/tex]. and its side [tex]\frac{\sqrt{900}}{2}\frac{1}{\sqrt{2}}[/tex]. The area (of one square) is [tex](\frac{\sqrt{900}}{2}\frac{1}{\sqrt{2}})^2=\frac{225}{2}[/tex]
finally the two areas combined (squares 2 and 4) would be 225
