Word Problem Using the Distance Formula
Question
Saad modifies the distance equation by taking the square of both sides.
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Word Problem Using the Distance Formula

Hi, I'm Bassem Saad for About.com, and this is a quick tip for solving word problems using the distance formula.Let's take a look at this word problem: Find all the points in the plane that are a distance of three units away from the point one, minus one. So let's find the distance between our mystery point and our point one, minus one. That is, we want to find the change in the x axis (that is x minus one), and the change in the y axis, which is y minus a minus one, or y plus one. And the distance has to be three units.Well, we can modify this equation by taking the square of both sides. And what we'll see is that we actually have an equation for a circle, with a radius of three and a center of one, minus one, which makes sense because every point on the circle is the same distance away from the center. Thanks for watching, and to learn more, visit us on the web at About.com.