One diagonal of a square is along the line 8x−15y=0 and one of its vertex is 1,2. Then the equations of the sides of the square passing through this vertex are

The slope of BD is 8/15 and the angle made by BD with DC and BC is 450. So, let the slope of DC be m, then.tan450=±m−8151+815mor 15+8m=±15m−8or m=237 and −723Hence, the equations of DC  and BC are y−2=237x−1or 23x−7y−9=0and y−2=723x−1or 7x+23y−53=0