A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).

A cube is a rectangular solid box with a height (h), length (l), and width (w). The volume is h x l x w and the surface area is 2lw x 2wh + 2lh.

To factor a quadratic expression, apply the FOIL (First, Outside, Inside, Last) method in reverse.

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.

4z + 6 > \( \frac{z}{-1} \)
-1 x (4z + 6) > z
(-1 x 4z) + (-1 x 6) > z
-4z - 6 > z
-4z - 6 - z > 0
-4z - z > 6
-5z > 6
z > \( \frac{6}{-5} \)
z > -1\(\frac{1}{5}\)

The formula for area is πr²:

a = πr²
a = π(3²)
a = 9π