The length of a rectangle is 2 times its width and its perimeter is 42 cm. A ssquare is formed by putting together 2 rectangles like this. Find the length and width of the edge and the area of this square.

"A ssquare is formed by putting together 2 rectangles like this."

Like what?

I assume you are placing two of the rectangles you describe together with long side against long side.

The original rectangle would be x by 2x and the new square would be 2x by 2x

from the original x +x+ 2x + 2x = 42

solve for x, and use that value to find the area of the square.

ok so i got 7 for the area of the square... how do i find the edge and length

the square has equal sides, the length and the width are the same:

s is side length

s2 = 7
take the square root of each side.

ok i did it again and for the length and the width i got 14 and 7 how do i find the edge?

no, you got 7 for the width of the original rectange, so its length is 14

which makes the square 14 by 14 for an area of 196

To find the edge length of the square, you would take the square root of the area. In this case, the area of the square is 196. Thus, the edge length is the square root of 196, which is 14.