In the Vectors in Three Dimensions section, we extend our understanding of vectors to three dimensions. Here we will review how to use the distance formula and write the equation of a circle in standard form.

Find the Distance Between Two Points

(See Module 2, Skills Review for Vectors in the Plane)

Write the Equation of a Circle in Standard Form

(also in Module 1, Skills Review for Polar Coordinates)

A circle is all points in a plane that are a fixed distance from a given point in the plane. The given point is called the center, (h,k), and the fixed distance is called the radius, r, of the circle.

Given a circle with center (h,k) and radius r, the equation of the circle in standard form is:

[latex](x-h)^2+(y-k)^2=r^2[/latex]