Question 1123420
Show that the points (12,9),(20,-6),(5,-14), and (-3,1) are the vertices of a square. What is the length of the diagonal?
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Label the points.
A(12,9), B(20,-6), C(5,-14), and D(-3,1)
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Find the lengths of AB, BC, CD and DA.
If they're equal, it's at least a parallelogram, and the points are labelled in order around it.
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If, in addition, AB is perpendicular to BC, it's a square.
Diagonal = AB*sqrt(2)