SOLUTION: the point (2,-5) is a vertex of square one whose sides lies on the line x-2y=7 calculate the area of square

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Question 1106794: the point (2,-5) is a vertex of square one whose sides lies on the line x-2y=7 calculate the area of square
Answer by ikleyn(52751) About Me  (Show Source):
You can put this solution on YOUR website!
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Notice that the point (2,-5) does not lie on the given line, because


2 - 2*(-5) = 2 + 10 = 12   IS NOT EQUAL  to 7.


Hence, we have the line, given by the equation, and a point outside this line.


Clearly, the measure of the side of the square is equal to the distance from the given point to the given line.


To find this distance, you can use the general formula

d = abs%28ap+%2B+bq+%2B+c%29%2Fsqrt%28a%5E2+%2B+b%5E2%29.     (*)


This formula gives the distance from the point (p,q) in the coordinate plane to the line whose equation is  ax + by + c = 0.


In our case,  d = abs%282-2%2A%28-5%29-7%29%2Fsqrt%281%5E2+%2B+%28-2%29%5E2%29 = abs%282%2B10-7%29%2Fsqrt%281%2B4%29 = 5%2Fsqrt%285%29 = sqrt%285%29.


Thus we determined that the square side is sqrt%285%29 units long.


Then the area of the square is  %28sqrt%285%29%29%5E2 = 5.

Solved.

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