The coordinate grid is composed of a horizontal x-axis and a vertical y-axis. The center of the grid, where the x-axis and y-axis meet, is called the origin.

A trapezoid is a quadrilateral with one set of parallel sides.

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 6 + 3 + 6 + 9
p = 24

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the > sign and the answer on the other.

-8b - 4 > -6 - 3b
-8b > -6 - 3b + 4
-8b + 3b > -6 + 4
-5b > -2
b > \( \frac{-2}{-5} \)
b > \(\frac{2}{5}\)

For parallel lines with a transversal, the following relationships apply:

• angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°)
• alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°)
• all acute angles (a° = c° = w° = z°) and all obtuse angles (b° = d° = x° = y°) equal each other
• same-side interior angles are supplementary and add up to 180° (e.g. a° + d° = 180°, d° + c° = 180°)

Applying these relationships starting with c° = 31, the value of w° is 31.