Hello, Dragon!

My solution is the same as Quick's . . . without the subscripts.

Three congruent rectangles are placed to form a larger rectangle

. . as shown with an area of 1350 cm^2

Find the area of a square that has the same perimeter as the larger rectangle.

Let = length of the small rectangles

and = width of the small rectangles. Code:

y x
* - - - - + - - - - - - - *
| | |
| | | y
| | |
x | + - - - - - - - +
| | |
| | | y
| | |
* - - - - + - - - - - - - *
y x

Since the left and right sides are equal:

. . and the rectangle looks like this: Code:

3y
* - - - - - - - - - - - - *
| |
| |
| |
2y | | 2y
| |
| |
| |
* - - - - - - - - - - - - *
3y

Its area is: .

Its perimeter is: .

Since the area is 1350 cm², we have: .

And its perimeter is: . cm.

The square with the same perimeter has a side of: cm.

The area of this square is: .