My Math Forum Distance between a point and a line

 Algebra Pre-Algebra and Basic Algebra Math Forum

 January 14th, 2010, 03:14 AM #1 Newbie   Joined: Jan 2010 Posts: 1 Thanks: 0 Distance between a point and a line Hi, I am using the formula: dist = |Ar+Bs+Ct +D| / sqrt(A^2 + B^2 + C^2) to find the distance between a point and a line for the line: Ax + By + Cz + D =0 and the Point: (r, s, t) Now that I have solved for the distance however, I would like to know which point on the line is closest to (r, s, t) How would I go about this? Thanks for any assistance
 January 14th, 2010, 10:54 AM #2 Senior Member   Joined: Feb 2009 From: Adelaide, Australia Posts: 1,519 Thanks: 3 Re: Distance between a point and a line Ax + By + Cz + D = 0 is a plane, not a line. Its normal is the vector (A,B,C). So you need to find where the line (r,s,t)+u(A,B,C) intersects Ax + By + Cz + D = 0. Solve u(A²+B²+C²)+(Ar+Bs+Ct+D) = 0 for u, and substitute that value into (r,s,t)+u(A,B,C).

 Tags distance, line, point

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post abcdefgh123 Algebra 2 January 4th, 2014 03:08 PM BattalGazi Algebra 16 March 30th, 2012 03:21 AM arnav.akash9 Algebra 1 November 16th, 2009 11:27 PM greg1313 Algebra 2 November 5th, 2008 01:58 PM BattalGazi Linear Algebra 1 December 31st, 1969 04:00 PM

 Contact - Home - Forums - Cryptocurrency Forum - Top