Bunuel
The diagonal distance of square A is one-half the diagonal distance across square B. What is the ratio of the area of square A to the area of square B?
A. 8 : 1
B. 2 : 1
C. 1 : 2
D. 1 : 4
E. 1 : 8
We can let the side of square a = a and the side of square b = b. We know that the ratio of a side of a square to its diagonal is x : x√2. Thus, the diagonal of square a is a√2, and the diagonal of square b is b√2. We are given that square a’s diagonal is half that of square b. Thus, we have:
a√2 = 1/2(b√2)
2a√2 = b√2
2a = b
4a^2 = b^2
a^2/b^2 = 1/4
Alternate Solution:
We know that the length of the diagonal of a square is √2 times the length of one of its sides. Thus, if we have two squares, the ratio of the lengths of sides of these squares is the same as the ratio of the lengths of their diagonals. Furthermore, since the area of a square is found by squaring the length of a side, the ratio of the areas of two squares is the square of the ratio of the lengths of the sides. Putting these two pieces of information together, we conclude that the ratio of the areas of the squares can be found simply by squaring the ratio of the lengths of the diagonals. Since the ratio of the lengths of the diagonals is 1:2, the ratio of the areas is 1:4.
Answer: D