Thursday

January 29, 2015

January 29, 2015

Posted by **Melba** on Tuesday, September 26, 2006 at 6:45pm.

Complete the squares to find the center of the circle.

X^2+Y^2-2X-8Y+1=0

(x-1)^2+(y-4)^2 - 16 =0

The center is (1,4) and the radius for the given circle is 4.

Now find the distance from (1,4) to the line to get the radius, then write the concentric circle's equation.

how do I get the distance if I don't have a point of intersection with the line or do I?

If you have a point (x1,y1), the distance to the line Ax+By+C=0 is

|Ax1+By1+c|/sqrt(A^2+B^2)

No, you don't have a point of intersection, you just want to find the distance and use that for the radius. The circle and line need to be tangent.

Thank you so much...

**Answer this Question**

**Related Questions**

calc - standard equations of circles that have centers on line 5x-2y=-21 and are...

geometry - two concentric circles with center E, AB = 40 CD = 24, CD is ...

math - can u help this the qustion is : A circle passes through the points (1,4...

steev - can u help this the qustion is : A circle passes through the points (1,4...

GEOMETRY INSCRIBED ANGLES MULTIPLE CHOICE QUESTION - segment BC is tangent to ...

Geometry - I have a circle with a Tangent line, DE, running along it and ...

Geometry - I have a circle with a Tangent line, DE, running along it and ...

math - a circle is tangent to the y-axis at y=3 and has one x-intercept at x=1 a...

Math - The points (4, –5) and (– 4, 1) are endpoints of a diameter of a circle...

Equations of a Circle - Write the standard for of the equation of the circle ...