Problem: A rhombus is given with one diagonal twice the length of the other diagonal. Express the side of the rhombus in terms of K, where K is the area of the rhombus in square inches:
Answer Choices:
A. K
B. 212K
C. 313K
D. 414K
E. none of these is correct
Solution:
Let the diagonals be d and 2d. Then 21d⋅2d=K or d2=K. Since s2=d2+(2d)2=K+4K=45K, s=215K.