can someone help me please.

9514 1404 393
Answer:
[tex]a=\sqrt{33}[/tex]
Step-by-step explanation:
The Pythagorean theorem tells you that the area of the square with side 'a' is the difference of the areas of the other two squares.
a² = 7² -4²
a² = 49 -16 = 33
a = √33