Bunuel
If the ratio of the areas of two squares is 2 : 1, then the ratio of the perimeters of the squares is
(A) 1 : 2
(B) \(1 :\sqrt{2}\)
(C) \(\sqrt{2}: 1\)
(D) 2 : 1
(E) 4 : 1
Choose valuesLet the smaller square, A, have side = 1
Area = s\(^2 = 1^2 = 1\)
Let the area of the larger square, B, = 2, to conform to the given ratio of areas as 2:1
The
side length of B:
Area = s\(^2\)
2 = s\(^2\)
\(s =\sqrt{2}\)
Ratio of perimeters? A square has four equal sides. The ratio of (side B): (side A) is the same whether you use all four sides or just one. Side B =
\(\sqrt{2}\). Side A = \(1\)
Ratio of perimeters, \(\frac{sideB}{sideA}=\frac{\sqrt{2}}{1}\)
Answer C
Scale factorScale factor is the amount by which each length in square A has been increased. (Length * length = area)
To enlarge area of A to B, the scale factor \(k\) was squared.
Square B = \((\frac{b}{a})^2 =\\
k^2\), where b = side length of B and a = side length of A.
Area of B is two times that of A. The scale factor to get the increase in size was \(k^2 =(\frac{2}{1})\)
To get back to one-dimensional length, i.e., ratio of perimeters \(\frac{b}{a}\):
Scaled down, B to A = \(\sqrt{k^2}\)=\(\frac{\sqrt{2}}{\sqrt{1}}\)=\(\frac{\sqrt{2}}{1}\)
Answer C