Point and Line Equation ```Name: Ani Status: student Age: 14 Location: N/A Country: N/A Date: N/A ``` Question: What is the formula for the distance between point A(x,y) and the line of equation y=mx+b. Replies: 1) A(x,y) lies on a line L perpendicular to y = mx + b. 2) L has slope - 1/m. 3) Use point-slope equation of straight line to obtain equation for L. 4) Solve L and y = mx + b simultaneously to get point B(x,y) on y = mx + b that is nearest A(x,y). 5) Now use distance formula on the points A and B. Have fun! Dr. Robinson The distance between a given point A(x0,y0) and a line ax+by+c=0 is d = absolute value of [(ax0+by0+c)/sqrt(a^2+b^2)] Just change the y=mx+b equation into the ax+by+c=0 form. Dr. C. Murphy This is a text-book problem. Since the new line is perpendicular to the old line, its slope is -1/m. The new line, furthermore, passes through the point A. With this information, you can find the constant C in the equation of the line, y=(-1/m)x+C. AK Dr. Ali Khounsary Advanced Photon Source Argonne National Laboratory Argonne, IL 60439 Click here to return to the Mathematics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012