3.2.15 Lines on a plane
condition: In a rhombus \( A B C D \) the coordinates of its center \( Q \) and vertex \( A \) are given, as well as its area \( S \). Find the equations of the sides of a rhombus. \[ Q(8,11), \quad A(1,4), \quad S=28 \text {. } \]
Equation of a straight line on a plane. Finding the equations of heights, bisectors and medians of a triangle, the intersection of lines.