How to find if rectangles are similar - GRE Quantitative Reasoning
Card 0 of 3
The perimeter of a rectangle is 14, and the diagonal connecting two vertices is 5.
Quantity A: 13
Quantity B: The area of the rectangle
The perimeter of a rectangle is 14, and the diagonal connecting two vertices is 5.
Quantity A: 13
Quantity B: The area of the rectangle
One potentially helpful first step is to draw the rectangle described in the problem statement:
After that, it's a matter of using the other information given. The perimeter is given as 14, and can be written in terms of the length and width of the rectangle:
Furthermore, notice that the diagonal forms the hypotenuse of a right triangle. The Pythagorean Theorem may be applied:
This provides two equations and two unknowns. Redefining the first equation to isolate 
gives:
Plugging this into the second equation in turn gives:
Which can be reduced to:
or
Note that there are two possibile values for 
; 3 or 4. The one chosen is irrelevant. Choosing a value 3, it is possible to then find a value for 
:
This in turn allows for the definition of the rectangle's area:
So Quantity B is 12, which is less than Quantity A.
One potentially helpful first step is to draw the rectangle described in the problem statement:
After that, it's a matter of using the other information given. The perimeter is given as 14, and can be written in terms of the length and width of the rectangle:
Furthermore, notice that the diagonal forms the hypotenuse of a right triangle. The Pythagorean Theorem may be applied:
This provides two equations and two unknowns. Redefining the first equation to isolate
Plugging this into the second equation in turn gives:
Which can be reduced to:
or
Note that there are two possibile values for
This in turn allows for the definition of the rectangle's area:
So Quantity B is 12, which is less than Quantity A.
Compare your answer with the correct one above
One rectangle has a height of 
and a width of 
. Which of the following is a possible perimeter of a similar rectangle, having one side that is 
?
One rectangle has a height of
Based on the information given, we know that 
could be either the longer or the shorter side of the similar rectangle. Similar rectangles have proportional sides. We might need to test both, but let us begin with the easier proportion, namely:
as 
For this proportion, you really do not even need fractions. You know that 
must be 
.
This means that the figure would have a perimeter of 
Luckily, this is one of the answers!
Based on the information given, we know that
For this proportion, you really do not even need fractions. You know that
This means that the figure would have a perimeter of
Luckily, this is one of the answers!
Compare your answer with the correct one above
One rectangle has sides of 
and 
. Which of the following pairs could be the sides of a rectangle similar to this one?
One rectangle has sides of
For this problem, you need to find the pair of sides that would reduce to the same ratio as the original set of sides. This is a little tricky at first, but consider the set:
and 
For this, you have:
Now, if you factor out 
, you have:
Thus, the proportions are the same, meaning that the two rectangles would be similar.
For this problem, you need to find the pair of sides that would reduce to the same ratio as the original set of sides. This is a little tricky at first, but consider the set:
For this, you have:
Now, if you factor out
Thus, the proportions are the same, meaning that the two rectangles would be similar.
Compare your answer with the correct one above