Answer:
The easiest way to solve this is
- plot the given points and connect
- find the missing vertex by adding parallel segments (red dotted) to segments (blue solid) formed by connecting adjacent points
- intersection of those segments is the required vertex
#6
A(-2,0), B(-2, -2), C(x, y), D(2, 2)
Connect adjacent points:
Point C will be (2, 4) in this case
#7
A(-1,-3), B(x,y), C(1, 2), D(-1, -2)
Connect adjacent points:
Point B will be (1, 1) in this case
