I’m 100% sure it’s the 3rd one :)
Answer:

Step-by-step explanation:
We can start by finding the third side of the triangle/the side of the square using the Pythagorean Theorem:

In this case the side length of the square would be represented by the variable "c" as it is the hypotenuse:




Since the area of a square is the side length square then...

The square root and the squared cancel out giving us...

Question 4:
2x-3
Because we don’t know how much Fernando has that would be where we fill in the variable giving you 2x then 3 dollars less will give you the -3 therefore 2x-3
Question 5:
1/2x+7
Because we don’t know Deb’s age that would be the variable and we are looking for half of Deb’s age giving you 1/2x then the 7 years more giving you the +7 hence 1/2x+7