**rectangular coordinate system**, the

**Cartesian coordinate system**consists of two perpendicular real number lines intersecting at zero. Positions on this grid system are identified using ordered pairs, (

*x*,

*y*). The center of the system (0, 0) is called the

**origin**. The

*x*-coordinate indicates horizontal distance from the origin and the

*y*-coordinate indicates vertical distance from the origin.

**Instructional Video**: Plotting Points on the Coordinate Plane

The horizontal number line, usually called the

*x*-axis, is typically used for the independent variable. The vertical real number line, usually called the

*y*-axis, is used for the dependent variable.

Ordered pairs with 0 as a coordinate do not lie in a quadrant; these points lie on an axis.

**Example**: Find the distance and midpoint between the two points: (3, 4) and (−1, 2).

**Example**: Find the distance and midpoint between the two points: (0, 0) and (−3, 4).

**Example**: Find the distance and midpoint between the two points: (−1,−1) and (1,1).

**Example**: Find the distance and midpoint between the two points: (−2,−5) and (−4,−3).

**Circle Word Problem**: If the diameter of a circle is defined by two points (−3, 4) and (7, 4), find the center and radius of the circle. (Hint: diameter = 2*radius)

**Area of a Circle**: Find the area of a circle given the center (−3, 3) and a point (3, 3) on the circle.

**Video Examples on YouTube**: