SOLUTION: please help me understand this and help me answer it The circle is tangent to line 5x + 12y= 26 and the center is at the origin

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: please help me understand this and help me answer it The circle is tangent to line 5x + 12y= 26 and the center is at the origin      Log On


   



Question 1142123: please help me understand this and help me answer it
The circle is tangent to line 5x + 12y= 26 and the center is at the origin

Found 2 solutions by greenestamps, ikleyn:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


You didn't ask a question; I will assume you want to know how to find the equation of the circle.

(1) The equation of a circle with center (h,k) and radius r is %28x-h%29%5E2%2B%28y-k%29%5E2+=+r%5E2. With center (0,0), the equation is x%5E2%2By%5E2+=+r%5E2.
I will guess that you knew that....

So to find the equation of the circle, you need to find the radius of the circle.

(2) A radius to a point of tangency is perpendicular to the tangent; it is therefore the shortest distance from the center of the circle to any point on the tangent.

(3) There is a concise formula for the shortest distance from a given point to a given line. You can use the given center (0,0) and the line 5x+12y=26 to find the radius. Then you will have all you need to write the equation of the circle.

Here is the formula for the (shortest) distance from a point (m,n) to a line with equation Ax+By+C=0. Note the equation of the line must be in that exact form.

abs%28%28Am%2BBn%2BC%29%2Fsqrt%28A%5E2%2BB%5E2%29%29

If you need more help to finish writing the equation, post a thank-you note describing what you have done on the problem or what part you are having difficulty with.

Answer by ikleyn(52798) About Me  (Show Source):
You can put this solution on YOUR website!
.

There are many similar solved problems in my lesson
    - Find the standard equation of a circle
in this site, so you can learn the subject from there.


Regarding this key formula for the distance of the point to the straight line,  given by an equation in a coordinate plane,
see the lessons
    - The distance from a point to a straight line in a coordinate plane
    - HOW TO calculate the distance from a point to a straight line in a coordinate plane
    - Using formula for the distance from a point to a straight line in a plane to solve word problems
in this site.