document.write( "Question 719222: The shortest distance between the point (−5,5) and the line y=3x−2 is? \n" ); document.write( "
Algebra.Com's Answer #441252 by MathLover1(20850)\"\" \"About 
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The shortest distance between the point and the line is the perpendicular distance between a point and the line.\r
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Solved by pluggable solver: Finding a distance between a point given by coordinates (x, y) and a line given by equation y=ax+b
We want to find the perpendicular distance between a point given by coordinates (\"-5\",\"5\")
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\n" ); document.write( " First, let's draw a diagram of general situation with point P (xo, yo) and
\n" ); document.write( " line L: y= a.x + b. The required distance is PC. (in the diagram below)
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\n" ); document.write( " Methodology
\n" ); document.write( " We will first find the vertices of the triangle in order to get the side lengths and then by applying
\n" ); document.write( " Sine Rule on right angle triangle PAB and PBC we will calculate the desired distance PC.
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\n" ); document.write( " Step1
\n" ); document.write( " Calculation of the vertices of triangle PAB:
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\n" ); document.write( " Draw a vertical line passing through the point 'P'. This line \"x=-5\" will cut the given line 'L'
\n" ); document.write( " at point 'A'. The X coordinate of A(x1) will be same as \"xo=-5\". To find the Y-coordinate of
\n" ); document.write( " 'A' we will use the fact that point 'A' lies on the given line 'L' and satisfies the equation
\n" ); document.write( " of the line 'L'
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\n" ); document.write( " Now, plug this \"x1=-5\" in to the equation of line: y=3*x+-2
\n" ); document.write( " \"y1=3%2A-5+%2B-2\"
\n" ); document.write( " \"y1=-17\"
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\n" ); document.write( " Hence, Point (A)(\"x1=-5\",\"y1=-17\")
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\n" ); document.write( " Similarly,
\n" ); document.write( " Draw a horizontal line passing through the point 'P'. This line \"y=5\" will cut the given line 'L'
\n" ); document.write( " at point 'B'. The Y coordinate of B(y2) will be same as \"yo=5\". To find the X-coordinate of
\n" ); document.write( " B we will use the fact that point 'B' lies on the given line 'L' and satisfies the equation
\n" ); document.write( " of the line 'L'
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\n" ); document.write( " Now, plug this \"y2=5\" in to the equation of line: y=3*x+-2
\n" ); document.write( " \"5=3%2Ax2%2B-2\"
\n" ); document.write( " \"x2=+%285--2%29%2F3\"
\n" ); document.write( " \"x2=2.33333333333333\"
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\n" ); document.write( " Hence, Point (B)(\"x2=2.33333333333333\",\"y2=5\")
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\n" ); document.write( " Now, we have all the vertices of the triangle PAB
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\n" ); document.write( " Step2
\n" ); document.write( " Calculation of the side lengths using distance formula:
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\n" ); document.write( " \"d=sqrt%28%28x1-x2%29%5E2+%2B+%28y1-y2%29%5E2%29\"
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\n" ); document.write( " Hence, The side lengths PA, PB and AB are
\n" ); document.write( " \"PA=22\"
\n" ); document.write( " \"PB=7.33333333333333\"
\n" ); document.write( " \"AB=23.1900361745681\"
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\n" ); document.write( " Step3
\n" ); document.write( " Apply Sine rule on common angle B in triangle PAB and triangle PBC.
\n" ); document.write( " Both triangle PAB and triangle PBC are right angle triangle and points 'A', 'B' and 'C' lay on the given line L.
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\n" ); document.write( " \"Sin%28B%29=+AP%2FAB=PC%2FBP\"
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\n" ); document.write( " \"PC=%28AP%2ABP%29%2FAB=+6.95701085237043\"
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\n" ); document.write( " PC is the required perpendicular distance of the point P (-5, 5) from line given
\n" ); document.write( " lineL1: y=3*x+-2.
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\n" ); document.write( " For better understanding of this concept, look at the Lesson based on the above concept.
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