SOLUTION: Find the distance of the line 8x-5y-15=0 from the point (-3,2)

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Question 1172220: Find the distance of the line 8x-5y-15=0 from the point (-3,2)
Found 2 solutions by mccravyedwin, ikleyn:
Answer by mccravyedwin(405) About Me  (Show Source):
You can put this solution on YOUR website!


You want to find the length of the green line.

The distance from the point (x1,y1)
to the line Ax+By+C=0 is given by this formula:
d = abs%28Ax%5B1%5D%2BBy%5B1%5D%2BC%29%2Fsqrt%28A%5E2%2BB%5E2%29

Plug in the formula and simplify. 

Edwin

Answer by ikleyn(52750) About Me  (Show Source):
You can put this solution on YOUR website!
.
Find the distance of the line 8x-5y-15=0 from the point (-3,2).
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There is a remarkable formula to calculate the distance from a given point to a given straight line in a coordinate plane.


    Let the straight line in a coordinate plane is defined in terms of its linear equation 

         a*x + b*y + c = 0,

    where "a", "b" and "c" are real numbers, and let P = (x%5B0%5D,y%5B0%5D) be the point in the coordinate plane. 

    Then the distance from the point P to the straight line is equal to

        d = abs%28a%2Ax%5B0%5D+%2B+b%2Ay%5B0%5D+%2B+c%29%2Fsqrt%28a%5E2+%2B+b%5E2%29.


Regarding this formula, see the lesson
    The distance from a point to a straight line in a coordinate plane
in this site.


Your straight line is 8x - 5y - 15 = 0.


So, the numbers in your case are  a= 8, b= -5, c= -15,  x%5B0%5D = -3,  y%5B0%5D= 2.


Substitute the given data  a= 8, b= -5, c= -15,  x%5B0%5D = -3,  y%5B0%5D= 2  into the formula to get the distance under the question


    abs%288%2A%28-3%29+%2B+%28-5%29%2A2+-+15%29%2Fsqrt%288%5E2%2B%28-5%29%5E2%29 = abs%28-49%29%2Fsqrt%2889%29 = 49%2Fsqrt%2889%29 = %2849%2Asqrt%2889%29%29%2F89 = 5.194  (rounded).


Answer.  The distance is  49%2Fsqrt%2889%29 = %2849%2Asqrt%2889%29%29%2F89 = 5.194  (rounded).

Solved.

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Regarding all details, deducing the formula, illustrations and solutions to other similar problems, 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
    - OVERVIEW of lessons on the distance from a point to a straight line in a coordinate plane
in this site.