a). The fourth corner of the rectangle is the point (7, 7).
There's no way I can explain it in text without confusing you. The best way for you to understand it is to take a pencil and a blank sheet of paper, draw an x-axis and a y-axis, and then mark dots at the three points given in the question.
The rectangle is 2 units wide and 4 units high. It floats in the air, standing 3 units above the x-axis.
b). The perimeter of the rectangle is 12 units.
c). Its area is 8 square units.