Hello!
Answer:

Explanation:
Let the width of the rectangle be x. So:
Width = x
Lenght = 13x
We know that the area of the rectangle is equal to 39m².
The area of the rectangle is equal to:

So, now, we have this equation:

Let's solve this equation to find the measure of both of the dimensions of the rectangle.:
▪ First, divide both sides by 13:

Simplify:

▪ Finally, calculate the square root of both sides:

Simplify:
because a lenght is always > 0.
So:
Width = √3
Lenght = 13√3
Conclusion:
The width of the rectangle is √3 meters and the length of the rectangle is 13√3 meters.