X represents the length of a deck. There are three parts to this equations. The 1. width, 2. the length, and 3. the 5 feet shorter. Using the key words, y = the width of a deck (uses the term is which means =) So that takes the width part out of the equation. Then, 5 feet shorter means -5 than a number. That takes away the 5 feet shorter part of the equation. That leaves x to equal the length of the deck.
You put 3 shapes together I believe
A line that is drawn straight through the midpoint of a circle and that has its end points on the circle border is called the diameter (d)
Half of the diameter, or the distance from the midpoint to the circle border, is called the radius of the circle (r).
The circumference of a circle is found using this formula:
C=π⋅D or C=2π⋅R