Pythagorean Theorem for finding equations for circles

The formula of the Pythagorean theorem can be also applied for finding a equation for a circle. With the equation you could find the exact value of any point in the circle or out or inside the cirlce.

For finding a point in the circle first you have to trace a line from the center of the cricle to the point. That will be the radius (r) or the hypotenuse of the triangle. Then you have to complete the rest of the triangle with a straight line from the point to the x-axis. That line will be one of the legs of the triangle (y). The leg that is left will be x.

Then, you have to aplly the formula that instead of being a²+b²=c² will be x²+y²=r². This will be the relationship among side lengths of a triangle with side x and y and radius r.

If the point is inside or outside the circle the equation will be an inequality. It means it woul be x²+y²r².