Quote:
Originally Posted by shadow123blast
5. The points (4, 0) and (−4, 0) are two nonconsecutive vertices
of a rhombus with an area of 80 square units. One of the other
vertices is (0, K) where K > 0. What is the value of K?

One formula for the area of a rhombus is area = (0.5)AB, where A and B are diagonals of the rhombus.
(0.5)(8)(2K) = 80
8K = 80
K = 10