Question

A square has an area of 25 cm. If it's perimeter increases by 4 cm, what is its area

Answer 1

A = s^2 and P = 4s. 
So if A = 25, then s^2 = 25 so s = 5. Then 4*s = 4*5 = 20 
The perimeter of a square with an area of 25cm^2 is 20cm. 
Increase the perimeter by 4 to get 24cm. Then 4s = 24 implies s = 6. Then s^2 = A = 6^2 = 36. 
Now the area is 36 cm^2