Answer:
area of Jonah's backyard is, 196 meter square
Explanation:
Perimeter(P) of square is given by:

where a is the side of thew square
As per the statement:
The perimeter of Jonah's square backyard is 56 meters
⇒

Using the perimeter formula to solve for a:

Divide both sides by 4 we have;

or
a = 14 m
Area of a square(A) is given by:

Substitute the given value of a = 14 m to get area;

Therefore, the the area of Jonah's backyard is, 196 meter square