In a rectangular coordinate system, what is the area of a rectangle whose vertices have the coordinates (-5, 1), (1, 1), (1, -4) and (-5, -4)?
Choose one.
A) 20
B) 30
C) 40
D) 55
E) 48

Rationale: length of side 1 = 5 + 1 = 6 length of side 2 = 4 + 1 = 5 area of rectangle = 6 * 5 = 30 b is the answer
Answer: B