Answer:
Step-by-step explanation:
For this exercise you need to remember that a Square is defined as a Quadrilateral whose sides are equal in lenght and all its interios angles measure 90 degrees.
Based on that definition, and observing the squarE given in the picture attached, you can write the following equation:
Then, you need to solve for the variable "x" in order to find its value. You get that this is:
Now, knowing the value of "x" you can susbstitute it into any expression that represents the side of the square, and then you must evaluate in order to find the lenght of the side.
You get: